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The objective of this study was to determine the effects of feeding starter diets containing either chopped wheat straw (WS), chopped alfalfa hay (ALF) or their mixture (WA), and forage free starter diet (CO) on feed and water intakes, growth rate, blood metabolites, feeding behavior, ruminal pH, and structural body characteristics of Holstein calves. Sixty newborn Holstein calves (30 males and 30 females) were blocked based on sex and randomly assigned to one of four dietary treatments. The treatments included feeding dry starter diets with 1) no forage (CO), 2) chopped wheat straw (WS), 3) chopped alfalfa hay (ALF), or 4) a 50:50 mixture of wheat straw and alfalfa hay (WA). The dietary inclusion rate of forage was 5% from d 3 to 21 and 10% from d 22 until weaning and 2 weeks post-weaning. The starter diets were offered as totally mixed rations. Feed intake of individual calves was measured daily and body weight (BW) was monitored biweekly. Jugular blood samples were taken to measure serum metabolites on d 21 and 63. The calves in the WS group had greater (P<0.05) starter DM (1327 vs. 902 (g/d]), and neutral detergent fiber (NDF) (233 vs. 98 (g/d]) intakes than calves in the CO group. Calves fed forage had greater acid-detergent fiber (ADF) intake than calves fed CO diet (P<0.01). The total starter intake preweaning (100 vs. 76 and 73 (kg]) and dry matter intake (DMI) post-weaning (63 vs. 43 and 42 (kg]) were greater (P<0.05) for WS compared with ALF and CO calves, respectively. The average daily gain (average daily gain (ADG), 727 vs. 633 (g/d]) and average BW (65 vs. 60 (kg]) tended to be greater for WS relative to others (P<0.10). The average final body weight (BW) (97.7 vs. 85.3 (kg]) and total post-weaning weight gain (13.4 vs. 9.5 (kg]) were greater in WS compared with ALF (P<0.05), but was similar among WS, CO and WA groups. Ruminal pH tended to be greater (P=0.09) for WS (6.28) and WA (6.36) than for CO (5.61) and ALF (5.88). There was a tendency to decrease in non-nutritive oral behaviors for WS (21 min/d) compared with CO (59 (min/d]). Overall, findings suggest that forage in calf starter diets (mashed) could improve DMI and growth, with chopped WS being more effective than ALF under the conditions of this study. To imply, the indigestible and physically effective fiber of WS was able to stabilize rumen conditions and successfully stimulate greater starter intake. [ABSTRACT FROM AUTHOR]

Abstract Background Consumers, the industry, and many farmers have shown increased interest in alternative management systems that allow for cow-calf contact (CCC) and this topic has become an important focus of research for a sustainable dairy industry. Among the many knowledge gaps still existing in this novel research field, there is a need for further research to investigate effects of CCC beyond the nursing period (i.e., after cow-calf separation). Moreover, multi-herd observational studies are scarce. Therefore, the aim of this study was to investigate the within-herd effect of CCC on machine milk yield and calf growth beyond separation. In this prospective cohort study, we studied all cows and their calves (Norwegian Red breed) born between September 1st 2021 and January 31th 2022 at three Norwegian dairy farms, investigating the impact of CCC on machine milk yield and calf average daily gain (ADG) after separation of the cow-calf pair. The follow-up period was 305 d for cows and six months for calves. Machine milk yield was automatically registered at each milking and calf heart girth was measured once a month. As various contact durations emerged, they were categorized into three groups: no contact (NC 0–3 d), short duration (4–30 d) and long duration (> 30 d). Data were analyzed with linear mixed models with the individual animal as the unit of interest. For cows, days in milk (DIM) from date of separation up to 305 DIM were included in the analysis as a continuous variable. For calves, age up to 195 d was used in the statistical analysis. Results We found no differences in machine milk yield after separation across the different contact groups: cows with no contact (n = 28), short duration (n = 51) and long duration (n = 27) of contact, all exhibited comparable milk yields from the time of separation until the end of lactation. Furthermore, in the case of calves, no disparities in average daily gain (ADG) were identified for any of the contact groups: calves with no contact (n = 39), short duration (n = 61) and long duration (n = 38) of contact, displayed comparable growth during the first six months of life. Conclusions Our findings indicate no negative effects of CCC on machine milk yield after separation, nor any sustained effects on calf growth under the conditions of this study. More multi-herd observational studies conducted on-farm is needed to expand the understanding of effects of CCC on cow and calf performance after separation.

Background: Consumers, the industry, and many farmers have shown increased interest in alternative management systems that allow for cow-calf contact (CCC) and this topic has become an important focus of research for a sustainable dairy industry. Among the many knowledge gaps still existing in this novel research field, there is a need for further research to investigate effects of CCC beyond the nursing period (i.e., after cow-calf separation). Moreover, multi-herd observational studies are scarce. Therefore, the aim of this study was to investigate the within-herd effect of CCC on machine milk yield and calf growth beyond separation. In this prospective cohort study, we studied all cows and their calves (Norwegian Red breed) born between September 1st 2021 and January 31th 2022 at three Norwegian dairy farms, investigating the impact of CCC on machine milk yield and calf average daily gain (ADG) after separation of the cow-calf pair. The follow-up period was 305 d for cows and six months for calves. Machine milk yield was automatically registered at each milking and calf heart girth was measured once a month. As various contact durations emerged, they were categorized into three groups: no contact (NC 0–3 d), short duration (4–30 d) and long duration (> 30 d). Data were analyzed with linear mixed models with the individual animal as the unit of interest. For cows, days in milk (DIM) from date of separation up to 305 DIM were included in the analysis as a continuous variable. For calves, age up to 195 d was used in the statistical analysis. Results: We found no differences in machine milk yield after separation across the different contact groups: cows with no contact (n = 28), short duration (n = 51) and long duration (n = 27) of contact, all exhibited comparable milk yields from the time of separation until the end of lactation. Furthermore, in the case of calves, no disparities in average daily gain (ADG) were identified for any of the contact groups: calves with no contact (n = 39), short duration (n = 61) and long duration (n = 38) of contact, displayed comparable growth during the first six months of life. Conclusions: Our findings indicate no negative effects of CCC on machine milk yield after separation, nor any sustained effects on calf growth under the conditions of this study. More multi-herd observational studies conducted on-farm is needed to expand the understanding of effects of CCC on cow and calf performance after separation. [ABSTRACT FROM AUTHOR]

ABSTRACT: The present study was intended to evaluate the effect of forage source (alfalfa hay; ALF vs. corn silage; CS) along with a supplemental fat source (soybean oil; SO vs. rumen-inert palm fatty acids; PF) on growth performance, nutrient digestibility, and ruminal fermentation in dairy calves. Forty-eight new-born Holstein female calves (3 d old) were assigned to one of 4 treatments: (1) alfalfa hay with soybean oil (ALF–SO); (2) alfalfa hay with palm fatty acids (ALF–PF); (3) corn silage with soybean oil (CS–SO); (4) corn silage with palm fatty acids (CS–PF). Starter diets had equal amounts of forage (100 g/kg dry matter; DM) and fat source (30 g/kg DM). Calves were fed a constant amount of milk (d 1 to 63) and had ad libitum access to water and starters (d 1 to 83). The lowest and greatest starter intakes during the preweaning period occurred in ALF–SO and CS–PF, respectively. This coincided with forage × fat source interaction for average daily gain (ADG) during preweaning. The forage source affected total DM intake and ADG over the entire period, body weight (BW) at weaning, and final BW with greater values in calves that received CS compared with ALF. The concentrations of total short-chain fatty acids and butyrate were increased, whereas concentration of acetate and acetate:propionate ratio were decreased in the rumen of calves fed CS compared with ALF. Feeding CS increased urinary excretion of allantoin and, as a trend, total purine derivatives (PD) and estimated microbial protein synthesis in comparison with ALF. The fat source affected starter intake, ADG, and BW postweaning with the highest values in PF. The digestibility of neutral detergent fiber, crude protein and, as a trend, organic matter were higher in calves fed PF compared with SO. Calves fed PF had lower ruminal ammonia-N concentration and urinary N excretion and greater urinary excretion of allantoin and total PD. Calves receiving SO had a lower ruminal protozoa population. In conclusion, supplementing starter diets with CS and PF is superior to ALF and SO. Interaction of the positive effects of CS and PF on performance underlines that concurrent supplementation of CS with PF is especially recommendable in young calves before weaning.

Winter and spring precipitation are predicted to increase in the Midwest region of the United States, causing muddy conditions. In a previous experiment, Angus cows (8 per treatment) were paired based on initial body weight (BW) and one cow from each pair was randomly allocated to either the mud or control treatment. Though cows consumed the same amount of dry matter, cows in the mud treatment weighed 37.4 kg less than cows in the control treatment by day 269 of gestation. The objective of this experiment was to evaluate developmental programming effects of steers born to cows in the mud treatment (MUD; n = 7) or the control treatment (CON; n = 6). Steers were weighed at birth and then weekly from approximately 56 d of age until weaning and were subjected to a glucose tolerance test (GTT) and adrenocorticotropic hormone (ACTH) challenge after weaning. Steers were then placed in the feedlot for an 84-d growing phase and were weighed weekly and 12th rib back fat (BF) and ribeye area (REA) were imaged every 28 d using ultrasonography. Data were analyzed as a randomized complete block design with repeated measurements when appropriate (SAS 9.4). Although there was a 37.4 kg decrease in BW of cows by the end of gestation, there was no evidence of a pen treatment effect on calf birth weight (P = 0.60) or weaning weight (P = 0.99). Additionally, there was no evidence of a pen treatment × day effect for steer BW from birth to weaning (P = 0.67) or growing phase BW (P = 0.60). There was evidence of a treatment × day of growing phase effect (P = 0.02) for BF, such that CON steers had greater BF on day 28 of the growing phase; however, there was no evidence of a treatment × day effect for REA (P = 0.20). Furthermore, there was no evidence of a pen treatment effect for the growing phase average daily gain (P = 0.74), dry matter intake (P = 0.65), gain:feed (P = 0.48), plasma glucose concentration (P = 0.67) or plasma insulin concentration (P = 0.61) in response to the GTT, or plasma cortisol concentration in response to the ACTH challenge (P = 0.51). These results indicate that while mud increased net energy requirements for cows in the MUD treatment, there were no subsequent effects observed for steer BW, gain:feed, or response to glucose and ACTH during the growing phase. [ABSTRACT FROM AUTHOR]

The present study was intended to evaluate the effect of forage source (alfalfa hay; ALF vs. corn silage; CS) along with a supplemental fat source (soybean oil; SO vs. rumen-inert palm fatty acids; PF) on growth performance, nutrient digestibility, and ruminal fermentation in dairy calves. Forty-eight new-born Holstein female calves (3 d old) were assigned to one of 4 treatments: (1) alfalfa hay with soybean oil (ALF–SO); (2) alfalfa hay with palm fatty acids (ALF–PF); (3) corn silage with soybean oil (CS–SO); (4) corn silage with palm fatty acids (CS–PF). Starter diets had equal amounts of forage (100 g/kg dry matter; DM) and fat source (30 g/kg DM). Calves were fed a constant amount of milk (d 1 to 63) and had ad libitum access to water and starters (d 1 to 83). The lowest and greatest starter intakes during the preweaning period occurred in ALF–SO and CS–PF, respectively. This coincided with forage × fat source interaction for average daily gain (ADG) during preweaning. The forage source affected total DM intake and ADG over the entire period, body weight (BW) at weaning, and final BW with greater values in calves that received CS compared with ALF. The concentrations of total short-chain fatty acids and butyrate were increased, whereas concentration of acetate and acetate:propionate ratio were decreased in the rumen of calves fed CS compared with ALF. Feeding CS increased urinary excretion of allantoin and, as a trend, total purine derivatives (PD) and estimated microbial protein synthesis in comparison with ALF. The fat source affected starter intake, ADG, and BW postweaning with the highest values in PF. The digestibility of neutral detergent fiber, crude protein and, as a trend, organic matter were higher in calves fed PF compared with SO. Calves fed PF had lower ruminal ammonia-N concentration and urinary N excretion and greater urinary excretion of allantoin and total PD. Calves receiving SO had a lower ruminal protozoa population. In conclusion, supplementing starter diets with CS and PF is superior to ALF and SO. Interaction of the positive effects of CS and PF on performance underlines that concurrent supplementation of CS with PF is especially recommendable in young calves before weaning. [ABSTRACT FROM AUTHOR]

The objectives of this study were to analyze calf performance traits and sex ratio frequencies in reciprocal Bos indicus–Bos taurus F2 Nellore–Angus calves (n = 539). The F2 calves were produced using reciprocal Angus-sired (AN) and Nellore-sired (NA) F1 sires and F1 dams, resulting in four F2 cross types. Calf weight traits were analyzed using mixed models. Deviations from 50% calf sex ratios were tested against expected binomial thresholds. Dam type influenced Julian birth date (p < 0.05) with calves from AN cows born 5 to 6 days earlier than calves from NA cows. Sire type and dam type affected birth weight (p < 0.05) with calves from NA parents approximately 2.5 kg heavier than those from AN parents; weaning weight did not differ for parent F1 type. However, an interaction between sire and dam types affected weaning weight (p = 0.038) where AN x AN calves were 5 to 8 kg lighter than other crosses. Sire type influenced calf sex distribution at birth (p = 0.036) and at weaning (p = 0.026) with NA sires producing over 66% male calves. These results suggest birth weight reciprocal differences due to parental line of descent typically observed among F1 Bos indicus–Bos taurus crosses can persist in subsequent generations. [ABSTRACT FROM AUTHOR]

Camel milk production and marketing within the peri-urban areas within pastoral areas is emerging and has high potential due to sendentarization and urbanization of an increasing number of local inhabitants. Performance of grazing camels in these areas is poor due to inadequate feed resources, particularly during the dry season. The objective of this study was to determine the effect of supplementing lactating camels with milled Acacia tortilis pods and ‘Chalbi salt’ on milk yield, calf growth and its economic potential in the peri-urban area of Marsabit town, Kenya. Twenty Somali camels in early lactation (1-4 weeks post-partum) and parities 2 or 3 and their calves were recruited for the study. The dams and their calves were penned and fed individually with the supplements where applicable. The treatments were: browsing only (B), browsing and ‘Chalbi salt’ (BC), 2 kg/day milled Acacia tortilis pods, ‘Chalbi salt’ and browsing (BC2A) and 4 kg/day milled Acacia tortilis pods, ‘Chalbi salt’ and browsing (BC4A). Five camels were randomly allocated to each treatment based on initial live weight in a completely randomized design and data collection done for 90 days. During each milking, the two left or right quarters were alternately reserved for the calf, while the remaining two were milked by hand. Milk yields were recorded daily in the morning and evening for 90 days while the calves were weighed on weekly basis for the same period. The overall total mean milk yield during the experimental period ranged from 233.0 to 298.0 litres during the short rains and dry season, respectively. The mean calf weight gains over the study period were 15.2, 19.0, 32.2 and 39.0 kg for B, BC, BC2A and BC4A, respectively, with BC4A and BC2A being higher than B. Supplementing camels under treatment BC4A was profitable as it resulted in both higher milk yield and calf weight gain and hence positive net gain.

Many male dairy calves are castrated when reared for beef production, but for dairy breeds the assessment of the longer-lasting pain associated with this procedure has received little scientific attention. In this study we assessed 2 methods: surgical (n = 10 calves) and rubber ring (n = 11). All calves were castrated at 28 d of age using multimodal pain control. During the 8 wk that followed, we recorded wound healing, local inflammation, body weight, milk and calf starter intake, lying time, and wound-directed behavior. Surgical wounds were fully healed on average 4 wk after the procedure, but only 1 calf in the rubber ring treatment fully healed within the 8-wk study. Inflammation was greater after rubber ring castration; skin temperature in the area around the lesion was 1.7 ± 0.35°C (mean ± standard deviation) higher than for the surgical treatment. Compared with surgically castrated calves, those castrated by rubber ring gained less weight over the study period (on average 11.9 ± 5.1 kg less), a difference due in part to lower intake of calf starter (on average 1.8 ± 0.6 kg less). Calves in the rubber ring treatment spent less time lying down (on average 4.2 ± 1.2% fewer scans per day) and licked their lesions more frequently (on average 16.0 ± 3.3 more licks per day). We conclude that the rubber ring calves experienced more pain in the weeks following the procedure and thus recommend that surgical castration be favored for preweaning dairy calves. [ABSTRACT FROM AUTHOR]

The objective of current study was to evaluate the growth performance of Sahiwal calves fed either milk or milk replacer (MR), offering at 10% vs.15% of their live body weight (BW). Thirty two male Sahiwal calves were randomly divided equally into four dietary treatments having 8 animals in each. The calves were fed either milk or MR and offered at either 10% or 15% of BW but not exceeding 5 L/d and 6 L/d, respectively until week 8. The amount of liquid offered was then reduced gradually to zero and the calves were weaned at 10 weeks of age. Calves were offered a calf starter (CS) ration having 19% CP with 2.9 Mcal ME/kg DM, from week second until each calf reached 120 kg. Average daily gain (ADG) was higher (600±12 vs. 553±12 g/d; P < 0.05) among milk-fed group compared to those fed MR; calves served liquid at 15% of BW were not different (591±12 vs. 562±12 g/d; P > 0.05) from those served 10% of BW. Calves fed milk reached target weight earlier (23.1 vs. 25.4 weeks; P < 0.05) than those fed MR; though no effect was noted for levels of feeding. Total production cost was highest (Rs. 41734±305) in calves fed milk at 15% of BW and was lowest (Rs.29900±305) in calves fed MR at 10% of BW. (.). Cost/ kg live weight gain was highest (Rs. 345±2.8) among those fed milk at 15% of BW and was lowest (Rs. 245±2.8) in those offered MR at 10% of BW. Thus, feeding Sahiwal calves MR at 10% of BW is economical; however, it delayed the days to reach the target weight. [ABSTRACT FROM AUTHOR]

Aim of the study: The effects of forage source (alfalfa hay; AH vs. wheat straw; WS) with rumen undegradable to degradable protein ratio [low ratio (LR) = 28:72; high ratio (HR) = 36:64] were evaluated in young dairy calves. Area of study: Arak, Iran. Material and methods: Forty-eight 3-d old female Holstein dairy calves (44.5 kg of BW) were allocated in four treatments: (1) AH with low dietary RUP:RDP ratio (AH-LR); (2) AH with high dietary RUP:RDP ratio (AH-HR); (3) WS with low dietary RUP:RDP ratio (WS-LR); and (4) WS with high dietary RUP:RDP ratio (WS-HR), being RDP and RUP rumen degradable and undegradable proteins, respectively. The calves weaned on d 53 of the experiment and remained in the study until d 73 of age. Main results: The average daily gain and feed efficiency were improved in dairy calves receiving HR diets compared to LR diets during the post-weaning period (p

Spray-dried plasma protein (SDP) has been shown to improve growth and intestinal function in young calves when included in milk replacers (MR) fed at conventional rates. Use of an SDP and wheat protein blend to replace a portion of whey protein has been shown to perform similarly to using an all-whey protein control MR. However, a trend in the dairy industry is to feed calves for greater rates of growth during the preweaning period. The purpose of this study was to determine the effects of increasing amounts of SDP inclusion in MR on growth and health of calves fed at a high plane of nutrition. Young (<7 d) Holstein calves were offered starter and assigned to 1 of 5 MR treatments: an all-milk protein (whey) control MR (0SDP, n = 26) or MR containing 5% SDP (5SDP, n = 20), 7.5% SDP (7.5SDP, n = 14), 10% SDP (10SDP, n = 20), or 12% of an approximate 1:1 SDP plus wheat protein blend (PW, n = 17). All MR were formulated to contain 26% CP and 16% fat and were fed at a maximum rate of 1 kg of powder (as fed) from d 8 to 36. Amounts of MR powder were decreased by 25%/wk from d 37 to weaning at d 57. Thereafter, calves were provided only starter feed until the end of the study at d 63. On d 4, 15, 36, and 57, intestinal permeability was assessed via oral administration of lactulose and d -mannitol followed by analysis of lactulose and mannitol in blood at 60 min after administration. Increasing SDP led to a small linear decrease in MR consumed. There was a tendency for a positive linear relationship between increasing SDP and average daily gain of body weight, and SDP had mixed effects on body frame variables. Increasing SDP tended to increase fecal scores and increased the amount of fluid therapy given. Diet had no effect on intestinal permeability. Increasing SDP led to an increase in serum total cholesterol and serum urea N and tended to have a quadratic effect on serum glucose concentration on d 36. Calves fed PW tended to have increased withers height, increased intestinal permeability on d 36, and an increased likelihood of being medicated for any reason or being medicated for respiratory illness, but growth and health were not different from the control diet otherwise. Feeding PW led to an increase in serum total cholesterol and tended to lead to increased serum glucose concentration on d 36. Results of this study indicate that SDP can be included at up to 10% as fed in the MR of calves fed at a high plane of nutrition (1 kg/d of MR powder, as fed) with improvements in average daily gain. Additionally, a 1:1 SDP plus wheat protein blend can be used at 12% inclusion with no difference in most health and growth parameters. [ABSTRACT FROM AUTHOR]

The consequences of supplementing Lys, Met, and Thr in milk replacers (MR) for calves have been widely studied, but scarce information exists about potential roles of other AA (whether essential or not). The effects on growth performance of supplementation of 4 different AA combinations in a mixed ration (25.4% crude protein and 20.3% fat) based on skim milk powder and whey protein concentrate were evaluated in 76 Holstein male calves (3 ± 1.7 d old). The 4 MR were as follows: CTRL with no AA supplementation; PG, supplying additional 0.3% Pro and 0.1% Gly; FY, supplying additional 0.2% Phe and 0.2% Tyr; and KMT, providing additional 0.62% Lys, 0.22% Met, and 0.61% Thr. All calves were fed the same milk allowance program and were weaned at 56 d of study. Concentrate intake was limited to minimize interference of potential differences in solid feed intake among treatments. Animals were weighed weekly, intakes recorded daily, and blood samples obtained at 2, 5, and 7 wk of study to determine serum urea and plasma AA concentrations. Plasma AA concentrations were explored using compositional data analysis, and their isometric log-ratio transformations were used to analyze their potential influence on ADG and serum urea concentration using a linear mixed-effects model. We detected no differences in calf performance and feed intake. Plasma relative concentration of the AA supplemented in the KMT and PG treatments increased in their respective treatments, and, in PG calves, a slight increase in the proportion of plasma Gly, Glu, and branched-chain AA was also observed. The proportions of plasma branched-chain AA, His, and Gln increased, and those of Thr, Arg, Lys, and Glu decreased with calves' age. A specific log-contrast balance formed by Arg, Thr, and Lys was found to be the main driver for lowering serum urea concentrations and increasing calf growth. The use of compositional mixed-effects models identified a cluster formed by the combination of Arg, Thr, and Lys, as a potential AA to optimize calf growth. [ABSTRACT FROM AUTHOR]

• Cow-calf contact increased pre-weaning calf growth and reduced labour at calving. • Full-time pasture-based cow-calf contact challenged calf health and daily labour. • Part-time cow-calf contact affected calf behaviour and post-weaning growth negatively. Preventing cow-calf contact in rearing systems has been scrutinised. This descriptive study investigated the effects of full-time contact outdoors on pasture (FT-O), part-time contact indoors (PT-I), or no contact indoors (NC-I) on calf health, behaviour, growth and labour in a pasture-based dairy system. Cows (n = 55) were balanced pre-calving on parity (16 primiparous and 39 multiparous), milk production (35 weeks) of previous lactation (4497 ± 193.8 kg), breed and predicted calving date. Contact pairs bonded for 48 h, whereas NC-I calves were separated from cows immediately, and remained in individual pens for three days before grouping. The FT-O pairs moved outdoors at 5 ± 3.3 days, only separated from cows for milking twice daily. Part-time cows were milked once-a-day (8:00) and grazed outdoors post-milking, returning indoors to calves from 15:00–8:00 the following morning. The NC-I calves were assigned to a feeding plan offering up to 9.5 L/day of milk replacer via automatic feeder. All calves had Ad libitum access to water, concentrates and forage. For NC-I calves, weaning started at 48 days, taking 12 days, for contact calves it started at 58 days, taking seven days. From birth to three weeks post-weaning, animal health and labour were evaluated twice-weekly, weight and linear body measurements were recorded weekly and behaviour was recorded weekly (daily during weaning). Following this, weighing was carried out fortnightly. Faecal related issues were seen most often in contact calves than NC-I calves. The PT-I calves also experienced eye issues more often than NC-I and FT-O calves. Illness resulted in 26 % of FT-O calves being removed from experiment (none removed from NC-I and PT-I). The PT-I calves expressed the most abnormal behaviours throughout weaning. Contact calves vocalised more at weaning than NC-I (7.8 % vs 1.5 % of time). The NC-I calves weighed less at 28 (49.0 vs 55.5 kg), 56 (69.0 vs 82.1 kg), 70 (79.0 vs 87.1 kg) and 77 (81.8 vs 90.8 kg) days than FT-O and PT-I calves. Labour associated with calving was greater for the NC-I system (00:15:56 ± 00:00:35) than contact systems (00:01:39 ± 00:00:35). Weekly labour was greater for the FT-O system (00:01:29 ± 00:00:05) than NC-I and PT-I systems (00:00:44 ± 00:00:05), which were similar. Weaning labour was negligible for NC-I calves (computerised feeder), but 00:02:08 ± 00:00:09 for contact systems, which were similar. To conclude, pre-weaning calf growth and reduced labour at calving as a result of cow-calf contact is challenged by calf health and human welfare (related to daily labour) in the FT-O system and by calf behaviour and stunted post-weaning growth in the PT-I system. Thus, cow-calf contact in pasture-based dairy systems require further research to safeguard calf and human welfare. [ABSTRACT FROM AUTHOR]

In this research communication we describe the performance of dairy cow−calf pairs in two cow-driven CCC-systems differing in cows' access to the calves through computer-controlled access gates (smart gates, SG). We investigated cows' machine milk yield in the automatic milking system (AMS), calf growth, and intake of supplemental milk and concentrate. Two groups each with four cow-calf pairs were housed in a system with a cow area, a calf creep and a meeting area. SG's controlled cow traffic between the meeting area and the cow area where cows could obtain feed, cubicles and the AMS. Calves had ad libitum access to supplemental milk and concentrate. During the suckling phase of 31 d, cow access to the meeting area was free 24 h/d (group 1) or restricted (group 2) based on milking permission. Following the suckling phase, cow access was gradually decreased over 9 d (separation phase). During the suckling phase, cows' machine milk yield (mean ± sd) in the AMS was 11.4 ± 6.38 kg/d. In the separation phase, the yield increased to 25.0 ± 10.37 kg/d. Calf average daily gain (ADG) was high during the suckling phase: 1.2 ± 0.74 kg. During the separation phase, ADG decreased to 0.4 ± 0.72 kg which may be related to a low intake of supplemental milk. Calves' concentrate intake increased with age, and all calves consumed >1 kg/d after separation. We conclude that cows nurse the calf in a cow-directed CCC system well resulting in high ADG, and AMS milk yields were, at least, partially maintained during the suckling phase. Although the AMS yields increased in response to separation, calf ADG was decreased. A low sample size limits interpretation beyond description but provides a basis for hypotheses regarding future research into CCC-systems. [ABSTRACT FROM AUTHOR]

The rates of development of 2 tissues in mammary glands, parenchyma (PAR) and the mammary fat pad (MFP), in response to nutrition in early life might have a major bearing on lifetime milk production. Historical studies reported that feeding greater amounts of dietary nutrients from postweaning to puberty increased growth rates of heifers and stimulated the growth of MFP at the expense of PAR, which might suggest compromised mammary development and future milk production. The current study sought to determine if a higher volume of whole milk (8 vs. 4 L/d) offered to calves would increase rates of growth and development of PAR in mammary glands at weaning (1 to 12 wk). To measure these tissues, we developed 2 simple methods to assess the size of PAR and MFP at the time of screening using ultrasound. We report that calves offered 8 L/d of whole milk had greater rates of growth until weaning (0.86 ± 0.06 vs. 0.81 ± 0.09 kg/d), compared with calves offered 4 L/d. Ultrasonography showed that despite the faster rates of growth in calves offered 8 L/d of milk/d, the ratio of PAR:MFP depth was 40% less at weaning in the front glands (34%) compared with calves offered 4 L of milk/d. Rear glands were less impaired. The ultrasound methods developed here might be useful to monitor the development of mammary glands in response to different nutritional regimens during the preweaning period. [ABSTRACT FROM AUTHOR]

Monitoring early growth in neonatal dairy calves provides insight into the effectiveness of a producer's nutrition program and helps monitor for sickness. The objective of this study was to validate whether a partial-weight scale attached to an automated milk feeder (Combi; DeLaval, Tumba, Sweden) could precisely and accurately estimate calf weights compared with twice-weekly weights of a calibrated electronic scale (gold standard; Brecknell PS1000; Avery Weigh-Tronix LLC, Fairmont, MN). Holstein heifers (n = 20) were enrolled in this study from birth until 84 d of age. All heifers were eligible to receive 10 L of milk replacer/d for 56 d and were subsequently weaned using a step-down strategy across 14 d. The automated milk feeder had a radio frequency identification panel placed directly above the scale such that calves had to stand with both front hooves on the scale platform to access milk from the nipple. An algorithm was created to summarize and clean the scale measurements of any non-biologically relevant data points. The relationship between the daily weight average from the partial scale and the electronic scale was analyzed using Pearson correlations, linear regressions, and Bland-Altman plots. Data from the partial weight scale were considered precise if the correlation coefficient and coefficient of determination were very high (>0.90) and the mean bias from the Bland-Altman plots included zero with the 95% interval of agreement. The partial-weight scale was considered accurate if the slope from the linear regression did not differ significantly from 1. We found a very high Pearson correlation coefficient (0.99) and coefficient of determination (0.99). Bland-Altman plots were deemed acceptable and nonbiased; the Bland-Altman difference (feeder weight − scale weight) was 0.45 ± 2.33 kg (mean ± standard deviation). The slope of the linear regression was not different from 1 (slope = 1.01; 95% confidence interval = 1.00–1.03), suggesting that the partial-weight scale was accurate. In summary, the partial-weight scale was validated, with a high precision and accurate estimate of weight in calves compared with the gold standard electronic scale. The partial-weight scale may be a useful tool for producers to estimate calf weight if a data cleaning algorithm is used. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess the seasonal effect of an embryo transfer program in the tropics on the donor response, recipient reproductive performance and calf growth from birth to weaning. This study included five-year records from 145 donors, 1149 embryo transfers (ET) and 609 in calves. The effect of the season (dry or wet) was evaluated at the time of embryo flushing, embryo transfer and birth of the calves. There was a seasonal effect on the yield and quality of the embryos. The number of nonfertilized and transferable good quality embryos increased in the wet season. For the recipients, the probability of pregnancy after an ET decreased by 6% for each year of the dam’s age. However, no seasonal effect was found when comparing ET calves with their control group (natural mating—NM), nevertheless, weaning weight was associated with birth body weight, treatment, sex of the calf, season at birth, year of treatment, and dam’s age. Calves born by NM had lower average daily gain (ADG), and male calves registered higher gains than females. Likewise, calves born during the rainy season had lower ADG compared with calves born during the dry season. In conclusion, this study shows that seasonal effect is more apparent in donor and calf performance than in the recipients.

Genetically similar nulliparous Polled Hereford heifers from a closed pedigree herd were used to evaluate the effects of dietary protein during the first and second trimester of gestation upon foetal, placental and postnatal growth. Heifers were randomly allocated into two groups at 35 days after artificial insemination (35 days post conception (dpc)) to a single bull and fed high (15.7% CP) or low (5.9% CP) protein in the first trimester (T1). At 90 dpc, half of each nutritional treatment group changed to a high- or low-protein diet for the second trimester until 180 dpc (T2). High protein intake in the second trimester increased birth weight in females (P=0.05), but there was no effect of treatment upon birth weight when taken over both sexes. Biparietal diameter was significantly increased by high protein in the second trimester with the effect being greater in the female (P=0.02), but also significant overall (P=0.05). Placental weight was positively correlated with birth weight, fibroblast volume and relative blood vessel volume (P

High average daily weight gain of calves before weaning is of vital importance for economic profitability in suckler cow industries. Furthermore, it could indicate the fitness of the animals. The aim of the present study was to identify possible influencing factors for calf growth as well as to analyse the relationships between udder traits of Angus suckler cows and average daily gain (ADG) of their calves kept extensively on pasture. From April 2016 to March 2017 the ADG from birth to weaning of 330 Angus calves on five farms in various regions of Germany was recorded. The average daily gain at weaning was 1,098 g. For statistical analysis a mixed linear model was used. Calves with higher birth weights showed higher ADG (p < 0.0001). Calves from primiparous dams had lower ADG than calves from multiparous dams (p < 0.05). Calves from cows with medium-sized udders had higher ADG (p < 0.05). In conclusion, calves of suckler cows with mediumsized udders had higher average daily gains, wherefore the use of udder volume as a functional trait in breeding of extensively kept suckler cows might be reasonable. [ABSTRACT FROM AUTHOR]

Calves are typically weaned from milk to solids once they reach a predetermined age or when they are consuming a predetermined intake of solids. The first aim of this study was to compare feeding behavior and performance of calves weaned based on age versus starter intake. The latter method can result in considerable variation in the age at which calves are weaned, so a secondary aim was to compare calves that weaned early or late when weaned based on starter intake. In experiment 1, dairy calves were randomly assigned to be either (1) weaned by age at d 70 (n = 16), or (2) weaned by intake, where calves were weaned based on starter intake (n = 16). All calves were fed using an automatic milk feeder and offered 12 L/d of milk until 30 d of age. On d 31, all calves had their milk rations reduced. Calves weaned by age were reduced to 6 L/d of milk over 5 d and received 6 L/d milk from d 35 until d 63, when milk was reduced over 7 d until complete weaning at d 70. For calves weaned by intake, the milk ration was reduced on d 31 to 75% of that calf's previous milk intake (3-d average) and further reduced by 25% when the calf met each of 3 targets for starter intake: 225, 675, and 1,300 g/d. Calves that failed to reach the final target by d 63 (failed-intake group; n = 6) were weaned over 7 d to complete weaning at d 70. Ten calves met all 3 starter intake targets (successful-intake group). In experiment 2, all calves were assigned to the weaned-by-intake treatment (n = 48). The weaning strategy was identical to that described for experiment 1, but calves were permitted up to d 84 to reach the final starter intake target. Forty-three calves met all 3 targets and were retrospectively divided into early-weaning (weaned before d 63; n = 31) and late-weaning (weaned on or after d 63; n = 12) categories. In both experiments, the weaning period was considered from the time of initial milk reduction at d 31 until complete weaning at d 70 (weaned by age) or when consuming 1,300 g/d (weaned by intake). Postweaning growth was monitored from weaning until final weight in the calf-rearing period at d 98 (experiment 1) and d 105 (experiment 2). Final weight in the grower period was measured at d 134 (experiment 1) and d 145 (experiment 2). In experiment 1, successful-intake calves (vs. calves weaned by age) consumed 125.3 ± 16.4 L less milk and 41.3 ± 9.3 kg more starter over the experimental period, engaged in more unrewarded visits to the milk feeder during weaning (11.1 ± 1.5 vs. 5.0 ± 1.3 visits/d), and achieved similar weights at the end of the grower period (188.2 ± 6.6 vs. 195.2 ± 5.7 kg). In experiment 2, calves that weaned by intake early (vs. late) consumed 93.3 ± 26.0 L less milk and 57.2 ± 12.2 kg more starter, engaged in a similar number of unrewarded visits during weaning (7.0 ± 0.6 vs. 7.6 ± 1.0 visits/d), had greater average daily gain during weaning (1.08 ± 0.02 vs. 0.94 ± 0.03 kg/d), and achieved greater final weights at the end of the grower period (203.2 ± 2.9 vs. 192.6 ± 4.2 kg). These results indicate that calves weaned based on starter intake can achieve similar weights to those weaned by age, despite consuming less milk. However, some calves will fail to meet starter intake targets unless given sufficient time to do so. Variation in preweaning feed intake provides an opportunity for individualized management of calves. [ABSTRACT FROM AUTHOR]

Grazing endophyte-infected, toxic tall fescue reduces cow/calf production; therefore, this study examines alternate strategies such as use of novel endophyte fescue varieties during late gestation and early lactation or genetic selection of resistant cows. Pregnant cows (n = 75) were randomly assigned to fescue endophyte type: 1) endophyte-infected ergot alkaloid producing tall fescue (E+) or 2) novel endophyte-infected, non-toxic tall fescue (NOV) within maternal (A|A, n = 38 and G|G, n = 37) DRD2 genotype to examine changes in cow/calf performance and milk production during late gestation and early lactation. Grazing E+ fescue pastures during late gestation reduced cow body weight gain but did not alter calf birth weight compared to NOV. Milk production and calf ADG during the first 30 day of lactation were lower for E+ than NOV. The calving rate was reduced, but not calving interval for E+ cows. The adjusted 205-day weight of calves was lower in those grazing E+ with their dams compared to NOV. There were no interactions between DRD2 genotype and fescue endophyte type indicating that genotype was not associated with response to E+ fescue in this study. Overall, grazing NOV tall fescue pastures rather than E+ during critical stages of production improved cow gain during late gestation, calving rate, early milk production and calf growth.

Selection for increased milk production across the United States has resulted in variable cow and calf productivity responses. The calf growth response variability may be due to the relationship between calf milk and forage intake, which nursing and grazing behavior may help explain. The objectives of this study were to determine the impact of increasing level of milk production on cow body weight (BW), body condition score (BCS), reproductive performance, calf growth, nursing, and grazing behaviors in the Nebraska Sandhills. In a 2-yr study, data were collected on 118 mature crossbred cow-calf pairs from Marchand May-calving herds. On approximately 30, 60, 90, 120, and 210 d postpartum, individual cow 24-h milk yield was estimated through weigh-suckle-weigh techniques. Cow BW and BCS were collected 14 d prior to calving, weekly from d 30 through breeding, and at weaning. Calf BW was recorded at each milking. Calf nursing and grazing behaviors were determined during 3-wk periods at EARLY (65.4 ± 10.0 d) and LATE (162 ± 22.3 d) lactation using high frequency (1 hz) global positioning system (GPS) data collected with neck collars. Milk area under the curve values were calculated to determine total milk production during lactation for each cow and all response variables were analyzed using linear regression analysis. Cow BW, BW change, and reproductive performance were not (P > 0.12) associated with total milk production, except for a tendency (P = 0.09) for lower BW at breeding with increased milk production. At weaning, cow BCS was negatively associated (P = 0.02) with increasing milk production but was not associated at any other physiological stage. Calf percent of time spent grazing was not affected (P = 0.33) by increasing dam milk production. However, percent of time nursing exhibited a tendency (P = 0.10) to decrease with increasing dam milk production. Pre-weaning calf BW was positively associated (P < 0.01) with increased milk production at each weigh date. A positive association of calf average daily gain (ADG) with increasing dam milk production was observed (P < 0.04) from birth to age 120 d with only a tendency (P = 0.09) for a positive association observed from age 120 d to weaning. However, steer ADG in the finishing phase was not associated (P = 0.63) with level of dam milk production. In this study and environmental conditions, increasing milk production had a positive increase in calf growth during the pre-weaning phase without any negative impact reproduction. [ABSTRACT FROM AUTHOR]

Genetically similar nulliparous Polled Hereford heifers from a closed pedigree herd were used to evaluate the effects of dietary protein during the first and second trimester of gestation upon foetal, placental and postnatal growth. Heifers were randomly allocated into two groups at 35 days after artificial insemination (35 days post conception (dpc)) to a single bull and fed high (15.7% CP) or low (5.9% CP) protein in the first trimester (T1). At 90 dpc, half of each nutritional treatment group changed to a high- or low-protein diet for the second trimester until 180 dpc (T2). High protein intake in the second trimester increased birth weight in females ( P = 0.05), but there was no effect of treatment upon birth weight when taken over both sexes. Biparietal diameter was significantly increased by high protein in the second trimester with the effect being greater in the female ( P = 0.02), but also significant overall ( P = 0.05). Placental weight was positively correlated with birth weight, fibroblast volume and relative blood vessel volume ( P<0.05). Placental fibroblast density was increased and trophoblast volume decreased in the high-protein first trimester treatment group (P<0.05). There was a trend for placental weight to be increased by high protein in the second trimester (P = 0.06). Calves from heifers fed the high-protein treatment in the second trimester weighed significantly more on all occasions preweaning (at 1 month ( P = 0.0004), 2 months ( P = 0.006), 3 months ( P = 0.002), 4 months ( P = 0.01), 5 months ( P = 0.03), 6 months ( P = 0.001)), and grew at a faster rate over the 6-month period. By 6 months of age, the calves from heifers fed high nutrition in the second trimester weighed 33 kg heavier than those fed the low diet in the second trimester. These results suggest that dietary protein in early pregnancy alters the development of the bovine placenta and calf growth to weaning. [ABSTRACT FROM AUTHOR]

Heat abatement strategies for pre-weaned calves are seldom adopted. Our objectives were to determine the effects of adding fans to barns on environmental conditions and growth, feed efficiency, concentration of metabolites and health of pre-weaned female Holstein calves. Calves born from July 15th to 30th of 2019 were eligible for enrollment. At birth (d 0), calves were assigned randomly to: SH (n = 125) – hutch under a barn with no cooling, SHF (n = 101) – hutch under a barn cooled through fans. Body weight (BW) and wither-height were measured at birth and d 68. Calves were evaluated thrice weekly (0700–1000 h) using the Calf Health Scoring Chart (UW-Madison). A sub-sample of hutches (SH = 26, SHF = 25) was evaluated for air velocity and temperature at 1000 and 1600 h thrice weekly and calves housed in these hutches were evaluated for rectal temperature (RT) at 1600 h and respiratory rate (RR) at 1000 and 1600 h. Calves were fed a liquid diet twice a day (d 2–18 = 5.56 L/d; d 19–49 = 7.58 L/d; d 50–56 = 3.84 L/d; d 57–63 = 1.64 L/d) and starter ad libitum starting on d 14. A sub-sample of calves (SH = 56, SHF = 44) had intakes of liquid feed and starter measured daily, BW and wither-height measured weekly from birth to d 68, and blood sampled on d 1, 14, 28, 42, 49, 52, 56, 58, 63 and 65 for the measurement of fatty acids, β-hydroxybutyrate, and glucose concentrations. The SHF treatment increased air velocity by 0.8 m/sec and reduced air temperature by 0.3 ºC. The SHF treatment reduced RT (38.70 ± 0.03 vs. 38.78 ± 0.02 °C) and the percentage of calves with hyperthermia (RT ≥ 39.2 °C; 20.6 ± 1.9 vs. 30.2 ± 2.0%) at 1000 h. Treatment did not affect feed efficiency (SH = 0.53 ± 0.01, SHF = 0.53 ± 0.01 g of BW gained/g of dry matter intake), nor did it affect BW (SH = 81.6 ± 0.7, SHF = 82.9 ± 0.8 kg) and wither-height (SH = 89.5 ± 0.3, SHF = 90.1 ± 0.3 cm) on d 68. Concentrations of metabolites were not affected by treatment. Cooling the environment through fans reduced RT and the risk of hyperthermia at 1000 h but it did not affect performance of pre-weaned Holstein calves. [ABSTRACT FROM AUTHOR]

The study examines the economics of different calf rearing systems and considers effects of suckling and milk feeding on production, health and welfare of dairy cows and growth, milk and feed use, health and welfare of calves. The economics of (i) no suckling, (ii) suckling for 3 days, (iii) suckling for 7 weeks, all assuming milk or milk replacer fed until weaning at 13 weeks, was compared with (iv) suckling for 13 weeks and no milk feeding. A linear programming (LP) model, maximizing profit on a dual purpose dairy-beef farm in lowland eastern Norway, was used for the comparison. Details on calf rearing methods, labor, weaning age, intake of milk, and solid feed were gathered for a sample of organic farms and grouped according to the length of the suckling period. The data were coupled with the National Dairy Herd Recording System (NDHRS) using cross-sectional data for the years 2008-2013. The results of the model study showed that suckling up to at least 7 weeks and longer than on most farms in the survey, had a positive influence on the farm economics. This was due to the positive influence on calf growth and health as well as lowered costs. Consequently, dual purpose dairy-beef farmers should be careful to sacrifice calf suckling and restrict calf milk feeding. Long suckling until weaning at 13 weeks was, however, unprofitable. [ABSTRACT FROM AUTHOR]

The objective of this study was to understand the associations of calf growth traits with subsequent milk yield and body weight (BW). Data were collected for 281 Holstein heifer calves from 6 different calf trials of varying lengths (4 to 8 wk) conducted at Pennsylvania State University between 2003 and 2010. Calves were classified as high, medium, or low for hip height, starter feed intake, BW, and growth rate. Milk yield and cow BW were recorded during subsequent lactations. In total, there were 169,734 daily milk records and 136,153 cow BW records available. Data were evaluated using mixed model equations. Separate models were used for each calf growth trait initially, followed by models that considered multiple growth measures. Each model included age at calving, treatment within trial, parity, days in milk, lactation, and one of the calf growth traits as well as the interaction between lactation and days in milk as fixed effects. Cow and calendar week by year were fitted as random effects. Heifers from the low hip height classification as calves produced less milk across lactations after accounting for BW differences. Cows from the medium BW classification as calves produced more milk in early lactation than cows from the high BW classification as calves after accounting for differences in height. Calves that grew more quickly, ate more, and weighed more were heavier as first-lactation heifers and as mature cows. Our results suggest that the type of preweaning growth is an important consideration for future milk yield. Calves that were the shortest had the lowest milk production potential and were the least likely to remain in the herd until first lactation. [ABSTRACT FROM AUTHOR]

Weaning is generally practiced in dairy and beef cattle for achieving better growth rates by giving balance feed in foreign countries. In indigenous dairy cattle it is necessary to evaluate the effect of weaning and suckling on calf growth parameters and reproductive performance of dams. Fifty eight primiparous Gir cows and their calves were taken in to consideration for the study of these two managemental system including disease resistance and its effect on milk yield and lactation length. Significant differences (P <0.05) were observed in average daily weight gain (0.320±0.011 vs 0.440±0.011 g), weekly body weight gain (2.21±0.080 vs 3.09±0.78 kg) and total weight gain after 3 months of study period (28.70±1.036 vs 40.18±1.019 kg) in favour of calves that sucked their dams. Among two groups of cows, lower incidence of mastitis was recorded in suckled as compared to weaned group of cows and diarrhoea was a less frequent problem in calves of suckling system. By suckling in Gir cows significantly more milk (1540.51±135.69 lit) could be harvested as compared to weaning group (992.27±257.57 lit). However, five cows in weaned group also attained exceptionally higher milk yield with greater lactation days. The mean calving interval (501.83±18.38 vs 407.90±16.89 days) and lactation length (338.03±23.45 vs 210.19±36.823 days) were significantly higher in suckled than the weaned cows. Therefore, it is necessary to evaluate these two managemental systems thoroughly for the economics of milk production and calf raising in indigenous primiparous Gir cows. [ABSTRACT FROM AUTHOR]

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The objective of this study was to investigate the comparison of two different milk feeding schedules on growth performance of Holstein calves. Fourteen Holstein calves were housed in individual boxes. Calves were divided into 2 groups (n= 7); first group was fed with whole milk with the amount of 10% of their body weight (Conventional Milk Feeding Program= CFP), while second group was fed with whole milk adjusted weekly according to their body weight (Adjusted Weekly Feeding Program= AFP), started from 7%. The experiment was applied on 4-days-old calves after colostrum feeding and weaned while calves were 56 days old. Final BW was found very close in each group (59.13± 1.15vs 57.38± 1.05 kg, respectively in CFP and AFP). Starter DMI was numerically greater in CFP compared to AFP during the pre-weaning period (0.860 ± 0.16 vs 0.754 ± 0.16 kg/d, respectively). Body measurements (BMs) were similar during the pre-weaning period in each group excluding Chest Girth (CG). Although the numerical differences were found among groups BW, BMs, Feed Conversion Ratio (FCR) and Fecal score, these differences were not significant. The calves' performance and health were not affected by the level of milk feeding during the pre-weaning period. [ABSTRACT FROM AUTHOR]

In traditional cattle systems in the tropics, the milk produced is generally shared between the calf and the cattle keeper. This literature review evaluates the socio-economic aspects related to milk production and milk use in traditional cattle systems and identifies the best strategies of milk allocation in order to improve food security and maximise income. The available literature indicates that milk, in terms of economic, social and subsistence value, is more valuable than meat. Thus, under the conditions that characterise traditional cattle systems in the tropics, it is appropriate to have a higher milk offtake at the expense of calf growth. This review also found that certain management practices, such as restricted suckling, can be useful to minimise mortality of calves, while improving milk offtake for human consumption. [ABSTRACT FROM AUTHOR]

The aims of the experiment were to evaluate the effects of source of trace minerals (TM) and plane of nutrition (PN) early in life on growth and health of transported calves. Ninety male Holstein calves <1 wk old were assigned to treatments in a 2 × 2 factorial arrangement of PN and TM source in a randomized complete block design. Calves assigned to low PN (LPN) received milk replacer [22% crude protein (CP), 20% fat, 568 g of powder/d for wk 1 to 4, and 284 g of powder/d for wk 5] plus ad libitum access to starter [18% CP, dry matter (DM) basis, for wk 1 to 12] and a limited amount of hay (0.5 kg/d as fed, for wk 10 to 12); LPN calves were weaned at 6 wk. During wk 13 to 20, LPN calves were fed 3.2 kg/d of grower mix (16% CP, DM basis) plus chopped hay for ad libitum intake. Calves assigned to high PN (HPN) received variable amounts of milk replacer (28% CP; 20% fat; and 810, 1,136, and 568 g of powder/d for wk 1, 2 to 6, and 7, respectively) plus ad libitum access to starter (22% CP, DM basis, wk 1 to 12) and limited hay (0.5 kg/d as fed, for wk 10 to 12); HPN calves were weaned at wk 7. Calves assigned to HPN were offered grower mix for ad libitum intake plus a limited amount of chopped hay (0.5 kg/d, as-fed basis) from wk 13 to 20. Milk replacers were formulated to contain balanced amounts of either inorganic (I) or organic (O) TM (50, 50, 10, and 100 mg/kg of Zn, Mn, Cu, and Fe, respectively), whereas respective ITM or OTM starters and growers contained Zn, Mn, Cu, and Co at 70, 55, 12, and 1 mg/kg. The HPN treatments increased final body weight and stature measurements, average daily gain, and gain-to-feed ratio through wk 20. Starter intake was lower for calves fed HPN. The OTM increased growth when supplemented to HPN but not when supplemented to LPN. During the liquid-feeding period, fecal scores were more fluid for calves fed HPN but measures of health status did not differ among diets. Results indicated that an enhanced nutritional program during early life allowed calves to have greater overall growth and maintain a normal health status throughout the preweaning period. High PN and OTM were synergistic in increasing early growth of calves. [ABSTRACT FROM AUTHOR]

Abstract: Various methods can be used to feed dairy calves that may influence calf performance and these include changing frequency of feeding or age at weaning. Two trials were conducted to determine effects of feeding frequency and weaning age on calf growth, health and rumen development, where 124 Holstein heifer and bull calves were weaned at 3, 4, 5 or 6 weeks of age. During Trial 1, milk replacer (12.5% DM; 22% CP, 15.6% fat) was fed at 10% BW twice per day until 1 week prior to weaning when intake was reduced to 5% BW. During Trial 2 calves were fed at 10% BW in two feedings until 14 days, then at 10% BW once daily until 1 week prior to weaning when milk replacer was reduced to 5% BW. Blood glucose and urea nitrogen, BW 4 h post-feeding, heart girth, hip height, and withers height 4 h post-feeding were obtained weekly. Growth and structural measurements were similar for all treatments up to 8 weeks of age in both trials. Blood constituents and health observations were not different between trials. Similar growth and performance between treatments in both trials through 8 weeks of age indicate that calf performance is not affected by weaning early and feeding once daily. [Copyright &y& Elsevier]

The objective of the study was to evaluate the effects of 3 targeted growth rates on adaptive (i.e., antigen-specific) immune responses of preruminant, milk replacer-fed calves. Calves (9.1 ± 2.4 d of age) were assigned randomly to one of 3 dietary treatments to achieve 3 targeted daily rates of gain [no growth (maintenance) = 0.0 kg/d, low growth = 0.55 kg/d, or high growth = 1.2 kg/d] over an 8-wk period. The NRC Nutrient Requirements of Dairy Cattle calf model computer program was used to estimate the milk replacer intakes needed to achieve target growth rates. All calves were fed a 30% crude protein, 20% fat, all-milk protein milk replacer reconstituted to 14% dry matter. Diets were formulated to ensure that protein would not be limiting. All calves were vaccinated 3 wk after initiation of dietary treatments with Mycobacterium bovis, strain bacillus Calmette-Guerin and ovalbumin. Growth rates for no-growth (0.11 kg/d), low-growth (0.58 kg/d), and high-growth (1.16 kg/d) calves differed throughout the experimental period. Blood glucose concentrations in high-growth calves increased with time and were higher than in low- and no-growth calves. Mononuclear and polymorphonuclear leukocyte percentages in peripheral blood were unaffected by growth rate but did change with advancing age. Percentages of CD4+ T cells increased with age in no-growth and low-growth calves, a characteristic of maturation, but failed to increase in high-growth calves. Growth rate did not affect the percentages of CD45RO+ (memory) CD4+ and CD8+ T cells, antigen (i.e., ovalbumin)-specific serum IgG concentrations, or antigen (i.e., purified protein derivative)-induced IFN-γ and nitric oxide secretion by mononuclear cell cultures. Antigen-elicited cutaneous delayed-type hypersensitivity responses of no-growth calves exceeded responses of low-growth, but not high- growth, calves. In resting- and antigen-stimulated cell cultures, viabilities of CD4+, CD8+, and γδTCR+ T cells from high-growth calves were lower than those of the same T cell subsets from no-growth and low-growth calves. Alternatively, resting cultures of mononuclear leukocytes from high-growth calves produced more nitric oxide than those from no-growth and low-growth calves. In conclusion, adaptive immune responses were affected minimally by growth rate. The results suggest that protein-energy malnutrition in the absence of weight loss is not detrimental to antigen-specific responses of neonatal vaccinated calves and that a high growth rate does not enhance these responses. The negative effect of a high growth rate on the viability of circulating T cell populations may influence infectious disease resistance of the calf. [ABSTRACT FROM AUTHOR]

Abstract: Lactation appears to be an influential factor for the adult size of male deer and thus, it could also influence the size of the antlers. This study examined the effects of lactation on body weight and antler size of male Iberian red deer up to 2 years of age. Several body and antler measurements were related to the production and composition of milk and calf growth during lactation. Results showed that calf weight gains during lactation affected body weight and other parameters of calves at 1 year of age, and there is evidence that, even in ad libitum food conditions during post weaning period, some lactation effects could extend up to 2 years of age. High percentage of milk protein resulted in increased antler weight or length. Results also suggested that body growth during this early stage might affect antler size positively through growth precocity. Thus, males that reached a higher weight at weaning also developed antlers earlier. Antlers that developed earlier were also heavier and had a greater base perimeter. [Copyright &y& Elsevier]

Simple Summary: It is well-known that embryo transfer is a powerful tool which can increase the number of offspring of donor cows, thus improving cattle efficiency. The recipient dams are vital in a successful embryo transfer program, as they will sustain the length of the pregnancy and directly impact the development of the embryo and the productive performance of the animal after birth. Evaluating the effect of season on donors, recipients and delivered offspring from a private farm, we found that the seasonal effect is more apparent in donor and calf performance than in the recipients. It seems to be that the performance of the calves measured by birth and weaning weight favors the embryo-transferred offspring. However, there is a bias towards measuring the performance of calves born by embryo transfer as their condition was favorable compared to calves born by natural mating, as the latter calved at pasture without supervision, whereas the former the recipient dams calved in selected pastures. The aim of this study was to assess the seasonal effect of an embryo transfer program in the tropics on the donor response, recipient reproductive performance and calf growth from birth to weaning. This study included five-year records from 145 donors, 1149 embryo transfers (ET) and 609 in calves. The effect of the season (dry or wet) was evaluated at the time of embryo flushing, embryo transfer and birth of the calves. There was a seasonal effect on the yield and quality of the embryos. The number of nonfertilized and transferable good quality embryos increased in the wet season. For the recipients, the probability of pregnancy after an ET decreased by 6% for each year of the dam's age. However, no seasonal effect was found when comparing ET calves with their control group (natural mating—NM), nevertheless, weaning weight was associated with birth body weight, treatment, sex of the calf, season at birth, year of treatment, and dam's age. Calves born by NM had lower average daily gain (ADG), and male calves registered higher gains than females. Likewise, calves born during the rainy season had lower ADG compared with calves born during the dry season. In conclusion, this study shows that seasonal effect is more apparent in donor and calf performance than in the recipients. [ABSTRACT FROM AUTHOR]

Grazing endophyte-infected, toxic tall fescue reduces cow/calf production; therefore, this study examines alternate strategies such as use of novel endophyte fescue varieties during late gestation and early lactation or genetic selection of resistant cows. Pregnant cows (n = 75) were randomly assigned to fescue endophyte type: 1) endophyte-infected ergot alkaloid producing tall fescue (E+) or 2) novel endophyte-infected, non-toxic tall fescue (NOV) within maternal (A|A, n = 38 and G|G, n = 37) DRD2 genotype to examine changes in cow/calf performance and milk production during late gestation and early lactation. Grazing E+ fescue pastures during late gestation reduced cow body weight gain but did not alter calf birth weight compared to NOV. Milk production and calf ADG during the first 30 day of lactation were lower for E+ than NOV. The calving rate was reduced, but not calving interval for E+ cows. The adjusted 205-day weight of calves was lower in those grazing E+ with their dams compared to NOV. There were no interactions between DRD2 genotype and fescue endophyte type indicating that genotype was not associated with response to E+ fescue in this study. Overall, grazing NOV tall fescue pastures rather than E+ during critical stages of production improved cow gain during late gestation, calving rate, early milk production and calf growth. [ABSTRACT FROM AUTHOR]

• Cow genotype and parity are primary factors influencing milk yield and pre-weaning calf growth. • Cow milk yield and corresponding pre-weaning calf growth for Dairybeef, Beef, Early-maturing and Late-maturing genotypes were 8.64, 6.38, 6.78, 8.20 kg/day and 960, 894, 890, and 965 g, respectively. • Multiparous cows produced proportionately 14.8% (1.05 kg/day) more milk and their calves had a 92 g higher daily growth rate than primiparous cows. • Calf growth response to an additional kg of milk was 47, 53, 51 and 55 g for Dairybeef, Beef, Early-maturing and Late-maturing genotypes, respectively. The objectives of this study were to quantitatively summarize factors associated with cow milk yield (MY) and calf growth response in pasture-based beef cow-calf suckler systems and to discern how cow genotype and parity influenced these responses. A dataset of 344 treatment mean observations was compiled from 69 studies that reported data on cow MY, and calf pre-weaning average daily live weight gain (ADG) and/or weaning weight (WW). Data were analysed using linear mixed effects models with study and region included as random effects. Models were developed for cow MY, calf ADG and WW response and each model was evaluated based on different model fit statistics. The final cow MY model included cow origin (Dairybeef or Beef), cow maturity (early-maturing (EM) or late-maturing (LM) genotypes) and parity. Dairybeef produced 35.4% more milk (8.64 vs. 6.38 kg/day) than Beef cows, and LM produced 20.9% more milk (8.20 vs. 6.78 kg/day) than EM genotypes (P < 0.001). Multiparous cows had a 14.8% higher MY (8.11 vs. 7.06 kg/day) compared to primiparous cows (P < 0.001). Lactation curve persistency was better (P < 0.05) for Beef and EM compared to Dairybeef and LM genotype cows, respectively. The final models of calf ADG and WW included cow origin, cow maturity and parity. Calves from Dairybeef and LM cows were 14 and 20 kg heavier (P < 0.001) at weaning (210-day adjusted) compared to those from Beef and EM genotype cows, respectively. Calves from multiparous cows were 13 kg heavier at weaning than those from primiparous cows (P < 0.001). The response in calf ADG associated with a 1 kg increase in cow daily MY was 47 and 53 g for Dairybeef and Beef cows, respectively (P < 0.001). Corresponding responses for EM and LM cows were 51 and 55 g (P < 0.001). In conclusion, the relationships between cow MY and calf pre-weaning growth, as well as the quantitative impact of cow genotype and parity were determined for pasture-based beef suckler systems; the coefficients generated can be used for improving beef cow-calf management strategies, beef cattle breeding programmes and bio-economic modelling purposes. [ABSTRACT FROM AUTHOR]

In this research communication we describe the performance of dairy cow-calf pairs in two cow-driven CCC-systems differing in cows' access to the calves through computer-controlled access gates (smart gates, SG). We investigated cows' machine milk yield in the automatic milking system (AMS), calf growth, and intake of supplemental milk and concentrate. Two groups each with four cow-calf pairs were housed in a system with a cow area, a calf creep and a meeting area. SG's controlled cow traffic between the meeting area and the cow area where cows could obtain feed, cubicles and the AMS. Calves had ad libitum access to supplemental milk and concentrate. During the suckling phase of 31 d, cow access to the meeting area was free 24 h/d (group 1) or restricted (group 2) based on milking permission. Following the suckling phase, cow access was gradually decreased over 9 d (separation phase). During the suckling phase, cows' machine milk yield (mean ± sd) in the AMS was 11.4 ± 6.38 kg/d. In the separation phase, the yield increased to 25.0 ± 10.37 kg/d. Calf average daily gain (ADG) was high during the suckling phase: 1.2 ± 0.74 kg. During the separation phase, ADG decreased to 0.4 ± 0.72 kg which may be related to a low intake of supplemental milk. Calves' concentrate intake increased with age, and all calves consumed >1 kg/d after separation. We conclude that cows nurse the calf in a cow-directed CCC system well resulting in high ADG, and AMS milk yields were, at least, partially maintained during the suckling phase. Although the AMS yields increased in response to separation, calf ADG was decreased. A low sample size limits interpretation beyond description but provides a basis for hypotheses regarding future research into CCC-systems.