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Diet formulation in a pasture-based dairy system is a challenge as the quality and quantity of available pasture, which generally constitutes the base diet, is constantly changing. The objective of this paper is to cover a more in-depth review of the nutritional characteristics of pasture-based diets, identifying potential system, plant, and animal factors that condition pasture dietary inclusion in dairy cows. In practice, there is a wide diversity of pasture-based systems with predominant to minimal use of pasture requiring a more specific classification that potentially considers the amount and time of access to pasture, access to housing, length of grazing season, seasonality of calving, and level and method of supplementation. There are important differences in the nutritional quality between pasture species and even cultivars. However, under management practices that promote maintenance of pasture in a vegetative state as well as controlling the availability of pasture, it is possible to achieve high dry matter intakes (∼2.9%–3.4% of live weight) of pasture with moderate to high diet energy density, protein supply, and digestibility. The amount of pasture to include in the diet will depend on several factors, such as the type of production system, the cost of supplementary feeds, and the farmer's objectives, but inclusions of ∼40% to 50% of the diet seem to potentially reduce costs while apparently not limiting voluntary feed intake. Considering that there seems to be a continuum of intermediate management systems, a better understanding of the factors inherent to the feed ingredients used, as well as the use of nutrients by cows, and potential interactions between animal × system should be addressed in greater depth. This requires a meta-analysis approach, but given the diversity of the pasture-based system in practice, the existing information is highly fragmented. A clear definition of "subsystems" is necessary to direct the future research and development of mechanistic models. [Display omitted] [ABSTRACT FROM AUTHOR]

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Simple Summary: Understanding the trends in grazing and rumination behaviours and their variation can provide farmers with information about the health status, physiological state, productivity, and welfare of the animal. Considering this, we studied variations in grazing and rumination times in grazing dairy cows due to breed, lactation year, breeding worth, days in milk of the individual cow, and season and supplementary feeds. AfiCollar device was used to monitor and record the behaviours of grazing cows affiliated with Holstein-Friesian, Jersey, and KiwiCross breeds in different years of lactation during different seasons over three years. We found grazing time and rumination time varied among the individual cows, during different seasons (or stages of lactation), and when cows were fed with different supplements. Jersey cows, and in general, the cows in the first year of lactation relatively grazed for a longer period. Grazing time and rumination time were longer at the start of lactation in spring and shorter at the end of lactation in autumn. These findings could contribute to improving the measures for pasture management, and additional feed supply for a mixed herd comprising Jersey, Holstein-Friesian and KiwiCross breeds in different years of lactation during different seasons over the lactation period. This study investigated the variation in daily time spent grazing and rumination in spring-calved grazing dairy cows (n = 162) of three breeds, Holstein-Friesian (HFR), Jersey (JE), and KiwiCross (KC) with different breeding worth index, and in different years of lactation (1st, 2nd, 3rd, 4th). The cows were managed through a rotational grazing system and milked once a day at 05:00 a.m. The cows grazed mainly pasture and received supplementary feeds depending on the season. Automated AfiCollar device continuously monitored and recorded grazing time and rumination time of the individual cows throughout the lactation period for three study years (Year-1, Year-2, Year-3) with 54 cows per year. A general linear mixed model fitted with breed × lactation year with days in milk (DIM), breeding worth (BW) index value, individual cow, season, and feed, and their interactions was performed in SAS. Variance partitioning was used to quantify the effect size of study factors and their interactions. Individual cows, DIM, and BW (except Year-3) had effects on grazing and rumination times throughout the study years. Grazing time and rumination time were different for different seasons due to varying supplementary feeds. Grazing time varied among breeds in Year-2 and Year-3, and among lactation years only in Year-1. Although rumination time differed among breeds in Year-3, it remained the same within different lactation years. Grazing time and rumination time had a negative relationship with each other, and their regression lines varied for different seasons. The total variance explained by the model in grazing time was 36–39%, mainly contributed by the individual cow (12–20%), season (5–12%), supplementary feed (2–6%), breed (1–5%), and lactation year (1–6%). The total variance explained in rumination was 40–41%, mainly contributed by the individual cow (16–24%), season (2–17%), supplementary feed (1–2%), breed (2–8%), and lactation year (~1%). These findings could contribute to improving the measures for feed resource management during different seasons over the lactation period for a mixed herd comprising JE, HFR and KC breeds in different years of lactation. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the impact of sward diversification combined with a reduction of chemical nitrogen (N) fertilizer on the performance of spring calving grazing dairy cows within a farm systems experiment. Three farmlets were created; a monoculture of perennial ryegrass (Lolium perenne L.; PRG) fertilized with 250 kg N/ha (PRG-250N), a PRG - white clover (Trifolium repens; WC) sward fertilized with 125 kg N/ha (PRGWC-125N) and a multispecies sward (MSS) comprising of grasses, legumes and herbs also fertilized with 125 kg N/ha (MSS-125N). Each farmlet had its own herd of dairy cows on a total area of 18.7 ha divided into 20 paddocks. Each herd was comprised of pure Holstein-Friesian (HF) and HF Jersey crossbred (JFX) animals and randomly assigned through the 3 treatments. For 3 years (2021 to 2023), the performances of both swards (grass yield, botanical composition, nutritive value) and grazing animals (milk production and composition, body weight (BW) and body condition score (BCS)) were recorded. There were no significant differences in pasture production or sward nutritive value between sward systems and grazing season length was also similar (264 d). On average over the 3 years, PRGWC-125N contained 150 g/kg DM of legumes and the MSS-125N contained 160 g/kg DM legumes, 130 g/kg DM plantain and 40 g/kg DM chicory. Both individual cow milk and fat plus protein (Milk solids; MS) yield were lower for PRG-250N (5,018 and 452 kg, respectively), intermediate for PRGWC-125N (5,139 and 463 kg, respectively) and highest for MSS-125N (5,297 and 476 kg, respectively) while milk and MS production per hectare from grazing were similar during the study period (11,523 and 1,016 kg/ha, respectively). Breed also had a significant effect with the JFX having lower milk yield but higher fat and protein concentration compared with HF. This resulted in higher MS production per kg of BW for the JFX compared with HF (0.96 and 0.87 kg MS/kg BW, respectively). The results of this study highlight the possibility for more diverse pastures to reduce chemical N fertilizer input requirements and maintain pasture productivity while increasing animal performance within pasture-based spring calving systems., (The Authors. Published by Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).)

This study investigated the variation in daily time spent grazing and rumination in spring-calved grazing dairy cows (n = 162) of three breeds, Holstein-Friesian (HFR), Jersey (JE), and KiwiCross (KC) with different breeding worth index, and in different years of lactation (1st, 2nd, 3rd, 4th). The cows were managed through a rotational grazing system and milked once a day at 05:00 a.m. The cows grazed mainly pasture and received supplementary feeds depending on the season. Automated AfiCollar device continuously monitored and recorded grazing time and rumination time of the individual cows throughout the lactation period for three study years (Year-1, Year-2, Year-3) with 54 cows per year. A general linear mixed model fitted with breed × lactation year with days in milk (DIM), breeding worth (BW) index value, individual cow, season, and feed, and their interactions was performed in SAS. Variance partitioning was used to quantify the effect size of study factors and their interactions. Individual cows, DIM, and BW (except Year-3) had effects on grazing and rumination times throughout the study years. Grazing time and rumination time were different for different seasons due to varying supplementary feeds. Grazing time varied among breeds in Year-2 and Year-3, and among lactation years only in Year-1. Although rumination time differed among breeds in Year-3, it remained the same within different lactation years. Grazing time and rumination time had a negative relationship with each other, and their regression lines varied for different seasons. The total variance explained by the model in grazing time was 36–39%, mainly contributed by the individual cow (12–20%), season (5–12%), supplementary feed (2–6%), breed (1–5%), and lactation year (1–6%). The total variance explained in rumination was 40–41%, mainly contributed by the individual cow (16–24%), season (2–17%), supplementary feed (1–2%), breed (2–8%), and lactation year (~1%). These findings could contribute to improving the measures for feed resource management during different seasons over the lactation period for a mixed herd comprising JE, HFR and KC breeds in different years of lactation.

This study aimed to assess the effect of shelter provision during the prepartum period on lying, ruminating, and feeding behavior in outdoor-housed dairy cows exposed to winter weather conditions in a temperate climate. We also aimed to determine whether shelter provision during the prepartum period influenced blood analytes related to energy metabolism, body cleanliness, and health status. In this study, 2 cohorts of 12 multiparous Holstein prepartum cows were tested in winter. Twenty-five days before their expected calving date, the cows in each cohort were paired and randomly assigned to an open paddock without shelter or to one with access to an artificial shelter until calving. Shelter use, lying time, number of lying bouts, duration of lying bouts, rumination time, and feeding time were continuously recorded during the 3 wk before calving. Cows were assessed weekly for body cleanliness throughout the 3-wk prepartum period. A blood sample was taken from the coccygeal vein of each cow at wk −3, −2, −1, 1, 2, and 3 relative to calving date, and were assayed for nonesterified fatty acids (NEFA), β-hydroxybutyrate, and haptoglobin concentrations. Cases of clinical health disorders after calving were also recorded. The cows spent 60% of their daily time in the shelters, and for 75% of that time they were lying down. Cows with access to shelter during the prepartum period lay down around 3.2 h/d more than cows without shelter on wk −3 and −2 relative to calving. The cows with shelter access spent less time feeding during the morning (wk −3: 29.7 min; wk −2: 12.1 min; wk −1: 17.3 min) and afternoon (wk −3: 18.2 min; wk −2: 21.9 min) than cows without shelter access. As well, cows with shelter access showed a higher body cleanliness score (∼92 vs. ∼48%) and lower NEFA concentrations (wk −2: 0.27 vs. 0.44 mmol/L; wk −1: 0.46 vs. 0.64 mmol/L) in the precalving period, and lower haptoglobin concentrations in the first week postpartum (0.34 vs. 0.79 mg/mL) than cows without shelter access. We observed no treatment differences in daily rumination time, β-hydroxybutyrate concentrations, or postpartum health disorders. Despite the small number of dairy cows used in this study, these findings suggest that having access to a shelter during the prepartum period increases lying time, improves body cleanliness, and reduces adipose mobilization. Therefore, it is important to provide a protected area for the welfare of prepartum dairy cows exposed to winter climate conditions. [ABSTRACT FROM AUTHOR]

Earlier detection followed by efficient treatment can reduce the impact of lameness. Currently, locomotion scoring (LS) is the most widely used method of early detection but has significant limitations in pasture-based cattle and is not commonly used routinely in New Zealand. Scoring in the milking parlour may be more achievable, so this study compared an in-parlour scoring (IPS) technique with LS in pasture-based dairy cows. For nine months on two dairy farms, whole herd LS (4-point 0–3 scale) was followed 24 h later by IPS, with cows being milked. Observed for shifting weight, abnormal weight distribution, swollen heel or hock joint, and overgrown hoof. Every third cow was scored. Sensitivity and specificity of individual IPS indicators and one or more, two or more or three positive indicators for detecting cows with locomotion scores ≥ 2 were calculated. Using a threshold of two or more positive indicators were optimal (sensitivity > 92% and specificity > 98%). Utilising the IPS indicators, a decision tree machine learning procedure classified cows with locomotion score class ≥2 with a true positive rate of 75% and a false positive rate of 0.2%. IPS has the potential to be an alternative to LS on pasture-based dairy farms.

The objective was to evaluate the reproductive performance of frozen sex-sorted sperm at 4 × 106 sperm per dose (SexedULTRA 4M, Sexing Technologies, Navasota, TX) relative to frozen conventional sperm in seasonal-calving pasture-based dairy cows. Semen from Holstein-Friesian (n = 8) and Jersey (n = 2) bulls was used. Four of the Holstein bulls used were resident at or near a sex-sorting laboratory (Cogent, UK, or ST Benelux, the Netherlands). The remaining 6 bulls were located at studs in Ireland. For these 6 bulls, ejaculates were collected, diluted with transport medium, and couriered to Cogent in parcel shippers. Transit time from ejaculation to arrival at the sorting laboratory was 6 to 7 h. For all bulls, ejaculates were split and processed to provide frozen conventional sperm (CONV) at 15 × 106 sperm per straw and frozen sex-sorted (SS) sperm at 4 × 106 sperm per straw and used to inseminate lactating dairy cows after spontaneous estrus. Pregnancy diagnosis was performed by ultrasound scanning (n = 7,246 records available for analysis). Generalized linear mixed models were used to examine effects on pregnancy per AI (P/AI) at first artificial insemination, with sperm treatment (CONV vs. SS), bull (n = 10), and treatment × bull interaction as the fixed effects, and herd (n = 142) as a random effect. Overall, P/AI was greater for cows inseminated with CONV than for those inseminated with SS (59.9% vs. 45.5%; 76.0% relative to CONV). This study was not designed to compare resident bulls vs. shipped ejaculates, but the magnitude of the difference between P/AI achieved by CONV and SS was apparently less for resident bulls (60.3% vs. 50.2%) than for shipped ejaculates (58.6% vs. 40.7%). We discovered a treatment × bull interaction for shipped ejaculates (P/AI ranged from 45 to 86% relative to CONV) but not for the resident bulls (P/AI ranged from 81 to 87% relative to CONV). Relative P/AI of SS compared with CONV was greater in cows with high or average fertility potential (76.1% and 78.3%, respectively) than in cows with low fertility potential (58.1%). In 33.1% of the enrolled herds, the P/AI achieved with SS was 90% or more of the P/AI achieved with CONV; this was mainly explained by herds in which SS performed exceptionally well but CONV performed poorly. In conclusion, SS had lower overall P/AI compared with CONV; however, P/AI achieved with SS was dependent on the bull, fertility potential of the cow, and herd. Strategies to improve the P/AI with SS in seasonal-calving pasture-based lactating dairy cows require further research. [ABSTRACT FROM AUTHOR]

This study aimed to determine if a diet change from a mixed system to a confinement system affects the milk production and composition, behavior and blood biochemistry of dairy cows. Cows were assigned randomly to one of the two treatments: cows fed with TMR (total‐mixed‐ration) (confined) throughout the period group fed TMR (GTMR, n = 15) and cows that changed their diet from pasture plus TMR to exclusive TMR at 70 ± 14 DIM (GCHD, n = 15). GTMR cows produced more milk and greater lactose and protein yield before the change of diet than GCHD cows (p ≤ .01), but these differences disappeared after the change. GCHD cows decreased the frequency of rumination and lying from before to after the change (p ≤ .03), but in GTMR cows no changes were observed. After diet change, GCHD cows had lower frequency of rumination and lying than GTMR cows (p ≤ .02). Before the change, GCHD cows had greater NEFA (non esterified fatty acids) concentrations than GTMR cows (p = .002). Abrupt change from a mixed system to a confined system was favorable on blood biochemical and milk variables of dairy cows. However, in relation to behavior, the cows expressed difficulties to adapt quickly to the abrupt change of system. [ABSTRACT FROM AUTHOR]

Our objective in this study was to evaluate the reproductive performance of dairy heifers and cows inseminated with fresh or frozen sex-sorted semen (SS) in seasonal-calving pasture-based dairy herds. Ejaculates of 10 Holstein-Friesian bulls were split and processed to provide (1) fresh conventional semen at 3 × 106 sperm per straw (CONV); (2) fresh SS at 1 × 106 sperm per straw (SS-1M); (3) fresh SS semen at 2 × 106 sperm per straw (SS-2M); and (4) frozen SS at 2 × 106 sperm per straw (SS-FRZ). Generalized linear mixed models were used to evaluate the effect of semen treatment and other explanatory variables on pregnancy per artificial insemination (P/AI) in heifers (n = 3,214) and lactating cows (n = 5,457). In heifers, P/AI was greater for inseminations with CONV (60.9%) than with SS-FRZ (52.8%) but did not differ from SS-1M (54.2%) or SS-2M (53.5%). Cows inseminated with CONV had greater P/AI (48.0%) than cows inseminated with SS, irrespective of treatment (SS-1M, SS-2M, and S-FROZEN; 37.6, 38.9, and 40.6%, respectively). None of the SS treatments differed from each other with regard to P/AI in either heifers or cows. The relative performance of SS compared with CONV was also examined [i.e., relative P/AI = (SS P/AI)/(CONV P/AI) × 100]. Frozen SS achieved relative P/AI >84%. Bull affected P/AI in both heifers and cows, but no bull by semen treatment interaction was observed. In heifers, P/AI increased with increasing predicted transmitting ability for milk protein percentage. In cows, P/AI increased with increasing Economic Breeding Index (EBI) and with days in milk (DIM) at AI but decreased with increasing EBI milk subindex, parity and with DIM2. Cows in parity ≥5 had the lowest P/AI and differed from cows in parities 1, 2, or 3. Dispatch-to-AI interval of fresh semen did not affect P/AI in lactating cows, but a dispatch-to-AI interval by bull interaction was detected whereby P/AI was constant for most bulls but increased with greater dispatch-to-AI intervals for 2 bulls. In conclusion, frozen SS achieved greater P/AI relative to conventional semen than was previously reported in lactating cows. Fresh SS did not achieve greater P/AI than frozen SS, regardless of whether the sperm dose per straw was 1 × 106 or 2 × 106. A bull effect for all semen treatments, as well as a dispatch-to-AI interval by bull interaction for fresh semen, highlights the importance of using a large team of bulls for breeding management. [ABSTRACT FROM AUTHOR]

Australian Merino ewes and lambs producing fine fibre wool for export are raised in the north-west of Uruguay in pasture-based systems. We studied the status of selenium and iodine in pregnant Merino ewes (10 per treatment) grazing in natural pasture, in natural pasture and supplemented with Se (0.1 mg Se/kg dry matter intake) and I (1 mg I/kg dry matter intake), or in natural pasture and supplemented with Se alone (0.1 mg Se/kg dry matter intake), during the last 30 days of gestation. Further, we evaluated the performance and wool quality of their offspring. Content of Se and I in natural pasture, in the sera of pregnant ewes, and in the wool of their offspring and levels of thyroidal hormones—TSH, T4, and free T3 (FT3)—in the sera of pregnant ewes were determined. The performance of lambs and the commercial parameters of fine fibre wool produced were measured. Results showed normal Se levels in serum (0.12–0.15 mg/l) in the ewes grazing in natural pasture (0.07–0.09 mg/kg DM) during late pregnancy. The observed increase in Se content in the pasture at lambing (0.11–0.16 mg/kg DM) improved serum Se levels (0.216 mg/l); however, the serum levels were not affected by the supplementation.I content in pasture showed adequate levels (0.50–0.60 mg/kg DM), which were reflected in the blood serum values 30 days prior to lambing (0.197–0.208 mg/l). However, at lambing, the I content in blood serum decreased (0.150 mg/l). Further, the supplementation did not modify the serum I levels (0.163–0.175 mg/l). An increase in FT3 levels in ewes at lambing could be associated with the increase in Se content in pasture and/or the adequate I content in pasture. No effect of supplementation was observed. Lambs showed good results regarding the quality of fine fibre wool and performance after supplementation with Se and I or Se alone and exhibited slightly improved Se and I content in wool. In conclusion, natural pasture provides adequate status in Se and I for the Merino ewes and their offspring without any additional beneficial effects of supplementation with Se and I or only Se.

Highlights • Crude glycerin improves the digestibility of ether extract. • Metabolic profile of goats differ with include crude glycerin. • Crude glycerin increase milk fat content. • Crude glycerin in the diet modulate milk fat composition in goats. Abstract Eight Alpine lactating goats with a body weight of 45.2 ± 7.5 kg and average milk production of 2.3 ± 0.183 kg/day were distributed in a double 4 × 4 Latin square to evaluate the effect of levels of crude glycerin in the feed supplement on the performance and metabolic parameters managed on Panicum maximum cv. Aruana pastures. The supplement consisted of corn grain, soybean meal, crude glycerin (0, 30, 60, and 90 g/kg in the dry matter of the supplement), calcitic limestone, and a mineral mixture. There was no effect of crude glycerin (CG) addition on the intake and apparent digestibility of dry matter and nutritional components, except for the ether extract. The milk fat content increased with the CG levels. The composition of C18:1 n-9, C18:2 n-6 cis , and C18:2 n-6 trans fatty acids in the milk had a quadratic response to CG levels, and the same effect was observed for the omega 3 and omega 6 polyunsaturated acids. Preprandial glucose levels decreased linearly with the addition of CG levels to the supplement, but were reestablished postprandially. The intake and excretion of nitrogen (N) in milk and the proportions of N absorbed and retained by the animal organism were not changed with the addition of CG to their feed supplement. The proportion of retained in relation to ingested N was higher when CG was added. Crude glycerin added to the supplement of lactating goats on pasture improves the N utilization by the animal organism and acts as a source of glucose in the first hours after feeding, in addition to elevating the polyunsaturated fatty acid content of milk. Therefore, this product can be included at up to 90 g/kg in the supplement of lactating goats on pasture. [ABSTRACT FROM AUTHOR]

The objective of this study was to identify the major electricity and water-consuming components of a pasture-based automatic milking (AM) system and to establish the daily and seasonal consumption trends. Electricity and water meters were installed on 7 seasonal calving pasture-based AM farms across Ireland. Electricity-consuming processes and equipment that were metered for consumption included milk cooling components, air compressors, AM unit(s), auxiliary water heaters, water pumps, lights, sockets, automatic manure scrapers, and so on. On-farm direct water-consuming processes and equipment were metered and included AM unit(s), auxiliary water heaters, tubular coolers, wash-down water pumps, livestock drinking water supply, and miscellaneous water taps. Data were collected and analyzed for the 12-mo period of 2015. The average AM farm examined had 114 cows, milking with 1.85 robots, performing a total of 105 milkings/AM unit per day. Total electricity consumption and costs were 62.6 Wh/L of milk produced and 0.91 cents/L, respectively. Milking (vacuum and milk pumping, within-AM unit water heating) had the largest electrical consumption at 33%, followed by air compressing (26%), milk cooling (18%), auxiliary water heating (8%), water pumping (4%), and other electricity-consuming processes (11%). Electricity costs followed a similar trend to that of consumption, with the milking process and water pumping accounting for the highest and lowest cost, respectively. The pattern of daily electricity consumption was similar across the lactation periods, with peak consumption occurring at 0100, 0800, and between 1300 and 1600 h. The trends in seasonal electricity consumption followed the seasonal milk production curve. Total water consumption was 3.7 L of water/L of milk produced. Water consumption associated with the dairy herd at the milking shed represented 42% of total water consumed on the farm. Daily water consumption trends indicated consumption to be lowest in the early morning period (0300–0600 h), followed by spikes in consumption between 1100 and 1400 h. Seasonal water trends followed the seasonal milk production curve, except for the month of May, when water consumption was reduced due to above average rainfall. This study provides a useful insight into the consumption of electricity and water on a pasture-based AM farms, while also facilitating the development of future strategies and technologies likely to increase the sustainability of AM systems. [ABSTRACT FROM AUTHOR]

Intensification of pasture-based dairy farming systems is usually associated with increased use of off-farm inputs to increase milk production per hectare, and additional environmental impacts may be associated with upstream production and delivery of these off-farm inputs. The objective of this study was to compare two levels of dairy farming intensification (i.e. high versus low) in pasture-based milk production systems with respect to (i) farm production and (ii) life cycle environmental indicators. The study considered 53 dairy farms in the Waikato region, New Zealand. Three farm attributes (stocking rate, amount of brought-in feeds and amount of nitrogen fertilizer used) were used to define a level of farming intensification (Intensification Index) for each dairy farm. The upper and lower quartiles of the dairy farms ranked on their Intensification Indices were chosen to represent high and low intensification groups, respectively. Twelve midpoint environmental indicators of the dairy systems were assessed using attributional Life Cycle Assessment with one kg of fat- and protein-corrected milk as a functional unit and a cradle-to-farm gate perspective as a system boundary. Compared with the low intensification group, the high intensification group had (on a per hectare basis) higher ( P < 0.001) stocking rate, total brought-in feeds and nitrogen fertilizer use, which led to greater milk yield per cow ( P < 0.01) and per hectare ( P < 0.001). The different levels of farming intensification did not affect total feed conversion efficiency ( P > 0.05). However, for the high intensification group, the results for 10 out of 12 environmental indicators per kg of fat- and protein-corrected milk were higher ( P < 0.05) than those in the low intensification group. The main drivers for the increases in most environmental indicator results were the production of brought-in feeds, manufacturing of agrichemicals and transportation of off-farm inputs for use on dairy farms. In contrast, increased pasture intake was negatively correlated ( P < 0.05) with all environmental impacts, indicating that efficient pasture management is also critical to mitigate environmental impacts. In conclusion, while an increase in intensification of pasture-based dairy farming systems led to increased milk production per cow and per hectare, it also resulted in increased environmental impacts for most indicators. Apart from increased resource use efficiency, increased pasture utilization efficiency is a promising measure to improve environmental sustainability of pasture-based dairy farming systems. [ABSTRACT FROM AUTHOR]

The productivity of grazing systems is primarily limited by the scale and efficiency of systems applied to the grazable land platform adjacent to the milking parlor. The objective of this study was to compare forage production, utilization and quality, milk production, and requirement for supplementary feeds for 2 different grazing platform stocking rate (GPSR) treatments over 4 yr. Animals were randomly allocated to 1 of 2 GPSR treatments: high-closed (HC; 3.1 cows/ha) and high-open (HO; 4.5 cows/ha), which were designed to represent alternative GPSR in a post-European Union milk quota, spring calving, pasture-based milk production system. Animal production data were analyzed using Proc MIXED of SAS with GPSR, year, and parity included as fixed effects in the final model. Within a seasonal spring calving grazing system, at high GPSR and offering moderate amounts of additional supplements based on pasture supply deficits, both systems produced more milk and fat plus protein per hectare in comparison with Irish commercial dairy farms. Although requiring additional supplementation, increased GPSR resulted in increased milk production per hectare but also in an increased requirement for concentrate and forage supplementation during lactation. No significant influence of GPSR was found on body weight and body condition score or reproductive performance during the 4-yr study period. In addition, GPSR also had no effect on pasture production, utilization, or quality during the study period. The strategic use of additional supplements with restricted pasture availability at higher GPSR maintained milk production per cow and significantly increased milk production per hectare. [ABSTRACT FROM AUTHOR]

Purpose:The aims of this paper are to (1) evaluate the main factors influencing grazing system technology adoption among new entrant (NE) dairy farmers within Europe and the Irish pasture-based dairy industry, and (2) to determine the extent to which economic factors influence decision-making around technology adoption and use among NEs to the Irish dairy industry. Methodology:Multivariate analysis is used to investigate the associations between region, education level, previous experience in dairy farming, herd size, age and the farmer's perception of the usefulness (PU) and ease-of-use of a technology (PEOU), and the likelihood of that technology being adopted. Findings:The results of this study identify a high rate of grazing, artificial insemination (AI) and financial management technology adoption among NE dairy farmers whose technology decisions are primarily motivated by financial considerations and are closely related to the PU and PEOU scores of the technology. Grassland measurement had the lowest adoption rate (51%) compared to AI (86%) and farm financial management (84%). Practical Implications:The substantial importance of PU and PEOU to technology adoption decisions indicates that future research, extension and education programmes should place increased emphasis on the benefits and usability of key technologies in addition to evaluating their scientific merit. Originality/Value:For the first time information assessing technology adoption amongst new dairy farmers is available. This has the potential to improve and increase extension and education for new dairy farmers in a future post-quota environment. [ABSTRACT FROM PUBLISHER]

Simple Summary: Lameness in dairy cows is a significant challenge globally. Early detection accompanied by effective treatment can reduce the number of cows that are lame and the impact of lameness. Currently, locomotion scoring by observing the gait posture of cows is the most widely used method of detecting lame cows. However, its use is limited, especially in pasture-based production systems like in New Zealand. One possible alternative to locomotion scoring is observing and recording cows for indicators of lameness while cows are being milked. We recorded the presence of four indicators (shifting weight, abnormal weight distribution, swollen heel or hock joint, and overgrown hoof) on two dairy farms in New Zealand. Two or more indicators were more useful predictors of higher locomotion scores (lameness). However, more results on more farms are needed before the in-parlour scoring procedure can be recommended as an alternative to locomotion scoring in pasture-based dairy cattle. Earlier detection followed by efficient treatment can reduce the impact of lameness. Currently, locomotion scoring (LS) is the most widely used method of early detection but has significant limitations in pasture-based cattle and is not commonly used routinely in New Zealand. Scoring in the milking parlour may be more achievable, so this study compared an in-parlour scoring (IPS) technique with LS in pasture-based dairy cows. For nine months on two dairy farms, whole herd LS (4-point 0–3 scale) was followed 24 h later by IPS, with cows being milked. Observed for shifting weight, abnormal weight distribution, swollen heel or hock joint, and overgrown hoof. Every third cow was scored. Sensitivity and specificity of individual IPS indicators and one or more, two or more or three positive indicators for detecting cows with locomotion scores ≥ 2 were calculated. Using a threshold of two or more positive indicators were optimal (sensitivity > 92% and specificity > 98%). Utilising the IPS indicators, a decision tree machine learning procedure classified cows with locomotion score class ≥2 with a true positive rate of 75% and a false positive rate of 0.2%. IPS has the potential to be an alternative to LS on pasture-based dairy farms. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the effect of diet, energy balance and milk production on oxidative stress in early-lactating, Holstein-Friesian dairy cows fed to produce either low or high levels of milk. Indicators of energy balance (non-esterified fatty acids, β-hydroxybutyrate, glucose and insulin-like growth factor-1) and indicators of oxidative stress (reactive oxygen metabolites and biological antioxidants) were measured in the first 5 weeks of lactation. Energy balance indicators showed that high producing animals had a lower degree of negative energy balance. Diet was found to have an indirect effect on the level of oxidative stress. Factors associated with a high level of oxidative stress were severe negative energy balance (mean -71 ± 6.85 27 MJ/cow/day, P < 0.05) and lower levels of milk production (mean 26.4 ± 0.07 28 L/cow/day, P < 0.05). Further studies will be required to more precisely determine the specific effects of diet, energy balance and milk production on such stress in dairy cows and to establish normal ranges for these biomarkers. [ABSTRACT FROM AUTHOR]

The U.S. dairy industry is undergoing rapid structural change, evolving from a structure including many small farmers in the Upper Midwest and Northeast to one that includes very large farms in new production regions. Small farms are struggling to retain competitiveness via improved management and low-input systems. Using data from USDA's Agricultural Resource Management Survey, we determine the extent of U.S. conventional and pasture-based milk production during 2003–2007, and estimate net returns, scale efficiency, and technical efficiency associated with the systems across different operation sizes. We compare the financial performance of small conventional and pasture-based producers with one another and with large-scale producers. A stochastic production frontier is used to analyze performance over the period for conventional and pasture technologies identified using a binomial logit model. Large conventional farms generally outperformed smaller farms using most economic measures—technical efficiency, various profitability measures, and returns to scale. [ABSTRACT FROM AUTHOR]

This study investigated the energy balance, metabolic changes, reproduction, and health in Australian Holstein-Friesian cows of average genetic merit fed to produce 6,000 L of milk/cow per lactation (restricted production; Rp) on a predominantly grazed pasture diet, or 9,000 L of milk/cow per lactation (high production: Hp) on a more intensive feeding regimen by using a partial mixed ration to supplement pasture. The mean 4% fat-corrected milk (FCM) and standard deviation achieved was 8,466 ± 1,162 L/cow per lactation for the Hp herd and 6,748 ± 787 L/cow per lactation for the Rp herd. During early lactation, the degree of estimated negative energy balance was less in the Hp cows than in the Rp cows (-16.1 vs. -29.1 MJ/cow per day, respectively). Consequently, the mobilization of body reserves was also lower in the Hp cows, and this was reflected in lower concentrations of nonesterified fatty acids (0.70 vs. 0.84 mmol/L) and B-hydroxybutyrate (0.51 vs. 0.69 mmol/L) and greater concentrations of glucose (3.51 vs. 3.34 mmol/L) and insulin-like growth factor-I (78.9 vs. 58.7 ng/mL) for Hp and Rp cows, respectively. After calving, body condition score and body weight decreased to a similar extent in both herds and did not reflect the differences in mobilization of body reserves between the 2 herds. Reproductive performance was not significantly related to level of milk yield. The mean interval from calving to first active corpus luteum was 33 (SD = 20) d postpartum, and there were 1.4 (SD = 0.8) estrus cycles before the beginning of the breeding period (>50 d postpartum). The interval from calving to pregnancy was 114 d, and the pregnancy rate after 12 wk of mating was 74%. The number of cows with ovarian abnormalities was also similar between the 2 herds. Cows with a long postpartum anestrus had the lowest concentration of insulin-like growth factor-I. The number of health-related disorders was also similar between the herds, with the exception of mastitis, for which the incidence was significantly greater in the Hp COWS. The results indicate that the production per cow could be increased from 6,748 L of FCM/cow per lactation for cows grazing pasture and supplemented with concentrates only at milking to 8,466 L of FCM/ cow per lactation, in one lactation, by supplementing pasture with a partial mixed ration. Despite the fact that production per cow increased substantially, the degree of estimated negative energy balance and the metabolic changes in early lactation were lower and reproductive performance was maintained. [ABSTRACT FROM AUTHOR]

The objective of this paper was to compare the economic efficiency of 3 divergent strains of Holstein-Friesian cows--high-production North American (HP), high-durability North American (HD), and New Zealand (NZ)--across a variety of Irish pasture-based production systems: Moorepark (MP), high concentrate (HC), and high stocking rate (HS). Physical performance data were obtained from a 5-yr study conducted previously. The economic performance of each strain and feed system was derived for 3 production scenarios: European Union (EU) milk quota applied at the farm level using predicted future prices and costs (S1); EU milk quota applied at the industry level, thus permitting quota leasing at predicted future prices and costs (S2); and EU milk quota applied at the industry level with a limitation on land availability (S3). The economic results showed that in a fixed milk quota scenario, the NZ strain in the MP and HS feed systems returned the highest profitability. The HD strain in the MP and HS feed systems proved the next most profitable, whereas the HP animals were least profitable in all feed systems. Similar to S1, in S2 the NZ were most profitable; however, the difference between the MP and HS was much smaller. The HP strain proved least profitable in all feed systems. In S3, the NZ strain was again most profitable; however, within that scenario the HS feed system was optimal. These results show that exclusive genetic selection for increased milk production results in reduced farm profitability because the productivity gains achieved are outweighed by associated increases in reproductive wastage costs in a pasture-based system. These results reinforce the economic value of genetic improvement based on a selection index encompassing traits of economic significance pertinent to the production environment. [ABSTRACT FROM AUTHOR]

• Early lactation once-a-day milking does not significantly reduce total lactation kg fat + kg protein. • Milking cows once daily for six or eight-weeks in early lactation reduces milk yield. • Milking time was up to 35% less when cows were milked once-a-day. • From week five of lactation somatic cell score was similar between treatments. The availability of labour during a compact calving period, can pose a challenge to dairy farmers. The objective of this study was to investigate, in comparison to twice-a-day (TAD) milking, the effect of short-term once-a-day (OAD) milking for four (OAD4), six (OAD6) or eight (OAD8) weeks directly post-calving on milk production, cow health and welfare. After each treatment finished their respective time on OAD milking cows reverted back to TAD milking for the remainder of lactation. A milk yield reduction of 21% was observed after the first four-weeks of lactation when milking OAD compared to TAD (618 kg/cow). When OAD milking continued until week six or eight of lactation milk yield reduction increased to 24 and 26%, respectively, compared to TAD. Following the 35-week lactation OAD6 (4,913 kg/cow) and OAD8 (4,815 kg/cow) treatments had a lower cumulative milk yield compared to the TAD cows (5,300 kg/cow); OAD4 were similar to all treatments (5,073 kg/cow). Following the first four weeks of the experiment the TAD herd had a higher milk fat, protein and lactose yield (+0.29, +0.17 and 0.28 kg/cow/day, respectively) than the three OAD herds which were not significantly different to each other (1.19, 0.72 and 0.95 kg/cow/day, respectively). Total milk fat, protein and lactose yields for the first six weeks of lactation were similar for all OAD treatments (44, 28 and 38 kg/cow, respectively) compared to the TAD treatment (54, 33,and 47 kg/cow, respectively). Following the first eight-weeks of lactation milk fat, protein and lactose yields were highest for the TAD (72, 45 and 65 kg/cow, respectively); OAD6 and OAD 8 were similar, OAD4 was similar to OAD6 but higher than OAD8. There was no difference in kg fat + kg protein (MSY) between treatments at the end of lactation. During the first four weeks of lactation milking cows OAD increased (+ 0.95 units) somatic cell score (SCS) compared to cows being milked TAD (3.26 units). From week five of lactation onwards there was no difference in SCS between any of the treatments. Milking time was consistently less (up to 35% less) when cows were milked OAD compared to TAD. The likelihood of milk leakage from udders pre-milking was significantly higher with OAD compared to TAD milking. There was no effect of treatment on locomotion score or fertility. The results of this study indicate that OAD milking for a short period of time in early lactation may be a viable option to reduce labour requirements without having a negative impact on cow milk production or welfare indicators. [ABSTRACT FROM AUTHOR]

Australian Merino ewes and lambs producing fine fibre wool for export are raised in the north-west of Uruguay in pasture-based systems. We studied the status of selenium and iodine in pregnant Merino ewes (10 per treatment) grazing in natural pasture, in natural pasture and supplemented with Se (0.1 mg Se/kg dry matter intake) and I (1 mg I/kg dry matter intake), or in natural pasture and supplemented with Se alone (0.1 mg Se/kg dry matter intake), during the last 30 days of gestation. Further, we evaluated the performance and wool quality of their offspring. Content of Se and I in natural pasture, in the sera of pregnant ewes, and in the wool of their offspring and levels of thyroidal hormones-TSH, T4, and free T3 (FT3)-in the sera of pregnant ewes were determined. The performance of lambs and the commercial parameters of fine fibre wool produced were measured. Results showed normal Se levels in serum (0.12-0.15 mg/l) in the ewes grazing in natural pasture (0.07-0.09 mg/kg DM) during late pregnancy. The observed increase in Se content in the pasture at lambing (0.11-0.16 mg/kg DM) improved serum Se levels (0.216 mg/l); however, the serum levels were not affected by the supplementation. I content in pasture showed adequate levels (0.50-0.60 mg/kg DM), which were reflected in the blood serum values 30 days prior to lambing (0.197-0.208 mg/l). However, at lambing, the I content in blood serum decreased (0.150 mg/l). Further, the supplementation did not modify the serum I levels (0.163-0.175 mg/l). An increase in FT3 levels in ewes at lambing could be associated with the increase in Se content in pasture and/or the adequate I content in pasture. No effect of supplementation was observed. Lambs showed good results regarding the quality of fine fibre wool and performance after supplementation with Se and I or Se alone and exhibited slightly improved Se and I content in wool. In conclusion, natural pasture provides adequate status in Se and I for the Merino ewes and their offspring without any additional beneficial effects of supplementation with Se and I or only Se., (© 2019 The Authors.)