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The objective of this study was to investigate the effects of delayed increase in milk allowance and type of gradual weaning program on the feed intake, health, and growth of male Holstein calves. Using a 2 × 2 factorial design, each male Holstein calf was randomly assigned to 1 of 2 milk level treatments and 1 of 2 weaning treatments upon arrival to a rearing facility. Calves were either assigned to a moderate (MM) or lower (LM) milk level treatment. All calves received the same milk program from arrival until d 12, increasing from 4 to 5 L/d (115 to 125 g/L) over the 12 d. On d 13, MM calves began receiving additional milk compared with LM calves until they were weaned, with MM offered milk increasing to a peak of 9 L/d (140 g/L). Calves on the MM treatment received a total of 35 kg of milk replacer over 45 d, compared with LM calves, who received a total of 25 kg of milk replacer over 45 d. Calves were also assigned to be weaned by either a 2-step gradual program or a 4-step gradual program. Calves assigned to the 2-step program had their milk reduced in 2 steps from d 30 to 45, and 4-step calves had their milk reduced in 4 steps from d 30 to 45. After d 46, calves received no milk but continued to be monitored until d 59. Calves had ad libitum access to water from arrival, and solid feed was offered from d 5 onward. No interactions of effects of milk level and weaning treatment were detected. By design, calves on the MM treatment consumed greater amounts of milk than LM calves in the preweaning phase from d 13 to 29 (6.1 vs. 4.8 L/d) and weaning phases from d 30 to 45 (4.7 vs. 3.2 L/d). The LM calves consumed greater amounts of solid feed than MM calves from d 22 to 29 of the preweaning phase, and from d 30 to 40 and d 43 to 45 of the weaning phase, whereas postweaning feed consumption was similar for both milk treatments. Calves in both milk treatments had similar blood β-hydroxybutyrate levels, indicating similar rumen development. Body weight and size measurements were similar between milk treatments across the study, although LM calves had a greater average daily gain than MM calves between d 38 and 46 (0.96 vs. 0.71 kg/d). Both gradual weaning treatments resulted in similar feed consumption, growth, and health parameters. Overall, the results indicate that delaying a moderate increase in milk until 12 d after arrival at a rearing facility provided no overall beneficial effect on growth or rumen development.

The objective of this study was to investigate the effect of 2 gradual weaning programs and 2 locations of solid feed within individual calf pens on feed intake, growth, and behavior of calves fed milk by an automated milk feeder. Using a 2 × 2 factorial design, 60 female calves were randomly assigned to 1 of 2 weaning treatments and 1 of 2 solid feed placement treatments. Calves were assigned to a continuous gradual weaning program (CG) or a multi-step gradual weaning program (MG). Calves assigned to the CG treatment had their milk allocation reduced in small, equal increments from 12.5 L/d on d 43 to 2 L/d on d 56. Calves assigned to the MG treatment were offered 10 L/d on d 43 to 45, 8 L/d on d 46 to 49, 6 L/d on d 50 to 52, and 3 L/d on d 53 to 56. Solid feed was placed either at the front of the pen adjacent (ADJ) to where the automated milk feeder offered milk or at the back of the pen on the opposite (OPP) side from where the milk was offered. All calves were offered 12.5 L/d of milk replacer from d 2 to 42, fresh solid feed (5% chopped wheat straw mixed with 95% calf starter pellet) from d 5 onward, and ad libitum water starting d 0. Calves were weaned from d 43 to 56 and additionally monitored from d 57 to 70. No interactions of effects of weaning and feed location treatment were detected. Both MG and CG calves had similar water and solid feed consumption, blood β-hydroxybutyrate concentrations, and behavior. By design, calves on the CG treatment consumed greater amounts of milk during the weaning phase than MG treatment calves (6.7 vs. 6.3 L/d), which resulted in milk drinking behavior differing between the treatments during the weaning phase. Although average daily gain and body weights were similar between treatments, MG calves had greater middle girth gain during wk 7 compared with CG calves (0.6 vs. 0.3 cm/d). Calves on the ADJ treatment consumed 16.7% more solid feed and 0.55 L/d more milk during the preweaning phase compared with OPP treatment calves. In all 3 phases, ADJ treatment calves consumed more water than OPP treatment calves. The ADJ calves spent more time consuming solid feed during the 10-wk period. The ADJ treatment calves had 10% greater average daily gain compared with OPP treatment calves during the preweaning phase. Overall, the results indicate that both gradual weaning treatments resulted in similar performance and behavior. However, placement of solid feed next to the milk source was demonstrated to increase feed, water, and milk intake during the preweaning stage, contributing to greater growth.

European starlings are an invasive bird species in North America that are known to cause damage to commercial dairies through the consumption of total mixed rations (TMR) destined for dairy cows. We hypothesized that large foraging flocks of starlings alter the physical composition of TMR, and that this change may be significant enough to affect milk production. To better determine if production losses could potentially occur in commercial dairies as a consequence of feed consumption by foraging flocks of starlings, we conducted controlled feeding experiments using a TMR sourced from a commercial dairy that is chronically plagued with seasonal starling damage. European starlings selected the high-energy fraction of the TMR and reduced starch and crude fat availability. Using the dairy National Research Council production model equations, the nutritional changes measured in the controlled feeding experiments could potentially reduce the productivity of dairies. Model output suggests that for Holsteins producing 32 kg of milk/d, total required net energy intake (NE I ) was 31.5 Mcal/d. Within the reference TMR, NE I supplied was 29.3 Mcal/d, whereas within the starling-consumed TMR NE I supplied was 27.7 Mcal/d. Following our nutrition experiments, we assessed the efficacy of pelleted feed as a deterrent strategy for bird damage management in commercial dairies. Six different pelleted feed treatments of differing diameter were offered to starlings. All pellets of 0.95 cm diameter or larger inhibited starling consumption by ≥79%.

Many dairy calves in the southwestern regions of the United States are raised in wooden hutches with 1.23 m2 of free space that house 3 calves individually. Producers claim that calves in hutch systems are not ready to wean and be placed in groups at the country-average age of 6 wk. Calves may remain in this individual housing system until as late as 10 wk of age. The objective of this study was to modify space allowance of hutches and evaluate weaning readiness using age at solid feed consumption, standing behaviors, and measures of immunity. Calves were randomly assigned at 4 d of age to conventional (CONV; 1.23 m2 of space; n = 18), moderate (MOD; 1.85 m2 of space; n = 17), or maximized (MAX; 3.71 m2 of space; n = 19) space allowance in hutches. These modifications also changed the number of calves housed per hutch from 3 (CONV) to 2 (MOD) and 1 (MAX). Calves were fed milk replacer via bottle twice daily until weaning and offered ad libitum feed throughout the experiment. Step-down weaning was initiated (Wi) at age 53 or 54 d by withdrawal of the p.m. bottle and was completed (Wc) 11 d later by removal of the a.m. milk replacer. Accelerometer data for standing behaviors were collected relative to Wi (3 consecutive days to represent -4 wk, -3 d, 3 d, and 3 and 5 wk). Blood samples were collected in the a.m. just before Wi (d 0) and at d 3, 11, 14, and 18 after Wi. Calves provided with more space (MOD and MAX) compared with CONV calves consumed feed at an earlier age and had slightly healthier erythrocytes, greater circulating glucose, and fewer circulating eosinophils. The CONV calves had haptoglobin (Hp) responses to the stressors of both Wi and Wc and had more IFN-γ from whole blood stimulated with phytohemagglutinin-P. The MAX calves had the least active neutrophils (phagocytosis and oxidative burst), but MOD calves' leukocytes secreted the most TNF-α from whole blood stimulated with lipopolysaccharide. Just before and after weaning, MAX calves spent more time per day in the standing position than CONV and MOD calves and had an Hp response to Wc, but MOD calves did not have an Hp response to Wi or Wc. Based on these results, MOD calves were the most ready for weaning; therefore, they potentially can be moved to group housing at an earlier age than CONV calves, thus improving animal welfare concerns over space allowance and individual housing.

We investigated the effect of social housing on the behavioral, intake, and physiological changes that occur at weaning for dairy calves fed milk ad libitum. These changes were evaluated during the weaning (d 40 to 48 of age) and postweaning (d 49 to 56 of age) stages. Twenty male Holstein calves were fed milk replacer ad libitum and weaned gradually by dilution over 9 d starting at d 40 of age. Calves were housed in pairs (10 calves) or individually (10 calves) from birth until the beginning of the postweaning phase, when all calves were paired. Feed and water intake were monitored daily. Feeding time was video-recorded, and blood β-hydroxybutyrate concentration was measured on alternate days beginning on d 40 and ending on d 56 of age. Electronic accelerometers continuously recorded standing and lying behavior for the 17-d study. Solid feed consumption increased by more than 5-fold over the weaning phase in all calves; during this phase pair-housed calves consumed more than twice (0.96 vs. 0.50 kg/d on d 48) that of the individually housed calves. Postweaning all calves rapidly increased their solid feed intake, and to a greater extent for previously individually housed calves, such that intake was similar between treatments by d 56. Free water intake was stable during weaning; however, a decrease (of 6.6 L) occurred in the constituent milk replacer water intake across this phase. As result, total water intake (free water + milk replacer water content) decreased (by 6.0 L) over the weaning phase between d 40 (14.9 L/d) and d 48 (8.9 L/d). On the first day postweaning (d 49), total water intake for all calves increased sharply (to 19.0 L/d) and then returned to a lower baseline (13.2 L/d) the next day (d 50), and slowly increased over the following week. During the weaning phase, feeding time and feeding rate increased with time for all calves, whereas pair-housed calves had greater feeding rates than individually housed calves (13.4 vs. 6.6 g of DM/min). After weaning, calves previously housed individually spent more time feeding in the early hours of the day than calves housed in pairs. Lying time and lying bout frequency decreased with calf age during the weaning period across treatments, and pair-housed calves tended to spend less time lying than individually housed calves (1,015 vs. 1,039 min/d) during this time period. Blood β-hydroxybutyrate increased across treatments over the weaning period, with the largest increase occurring between d 48 (0.05 mmol/L) and d 50 (0.2 mmol/L). These results show that calves alter their behavioral patterns during weaning and that housing calves in pairs may ease the transition from milk to solid feed.

Feed sorting is a natural behavior of dairy cows that can result in inconsistencies in the nutritive value of a total mixed ration (TMR). The objective of this study was to determine the effects of replacing high-moisture corn with glycerol on feed sorting and the feed intake pattern of transition dairy cows. Multiparous Holstein cows (n=26) were paired by expected calving date, housed in individual tie stalls, and fed diets containing either glycerol or high-moisture corn once daily from d -28 to +56 relative to calving. Glycerol was included at 11.5 and 10.8% of the ration dry matter for the pre- and postpartum diets, respectively. The feed consumption pattern was determined by measuring TMR disappearance during the intervals from 0 to 4 h, 4 to 8 h, 8 to 12 h, and 12 to 24 h relative to feed delivery. Feed sorting was determined on d -16, -9, 9, 16, and 51 relative to calving at 4, 8, 12 and 24 h after feeding. The TMR particle size profile was determined at feed delivery and at 4, 8, 12, and 24 after feed delivery by using the Penn State Particle Separator (Nasco, Fort Atkinson, WI) to yield long (19 mm), medium (19 mm,8 mm), short (8 mm,1.18 mm), and fine (1.18 mm) particles. Overall feed intake did not differ between diets and was 14.7±0.4 and 20.2±0.5 kg/d for the pre- and postpartum intervals, respectively. During the prepartum period, glycerol decreased the amount of feed consumed during the first 4h after feed delivery (7.22 vs. 5.59±0.35 kg; control vs. glycerol, respectively) but increased feed consumed from 12 through 24 h after feed delivery (2.22 vs. 3.82±0.35 kg; control vs. glycerol, respectively). Similar effects on the feed consumption pattern were observed after calving. During the prepartum period, cows fed the control diet sorted against long particles, whereas cows fed glycerol did not sort against long particles (77.2 vs. 101.5±3.50% of expected intake for control vs. glycerol; significant treatment effect). The data indicate that addition of glycerol to the TMR alters the feed consumption pattern to increase feed consumption late in the day at the expense of feed consumed immediately after feeding, and it reduces sorting behavior against long particles. Together, these may reduce diurnal variations in the rumen environment to promote greater rumen health in transition cows.

Individual dairy cow feed intake is closely related to the health and productive output of each cow, with healthy cows generally eating more feed than unhealthy cows. Incorporating the use of an automated system to monitor feed consumption for each cow may be beneficial for dairy farm management. This study examined the use of an inexpensive 3-dimensional video camera to measure feed volume, from which we derived feed weight. Proof-of-concept testing was conducted to determine the effectiveness and capability of the machine vision feed-scanning system and its possible use in feed intake monitoring. Such systems are ideal because they do not impede the workflow of the farm or interrupt feeding behavior. This is an improvement over existing systems that are labor and cost intensive. Our conducted experiments involve measuring feed volume at known weights, up to 22.68 kg, with the resulting volume and weight values analyzed by means of linear and quadratic least squares t-test regression analysis. The effects of feed positioning in the bin and near-range sensor limitations were also examined. The results showed that an estimation of feed weight from 3-dimensional scan of volume measurements could be made to within 0.5 kg of the physically measured feed weight using a digital scale. Future efforts will focus on extending this work to active bunks with multiple cows eating throughout the day and testing total mixed rations of varied composition.

Eighty female Holstein calves (12±4.1 d of age and 42±4.3 kg of BW) were collected from different herds, brought to the study site, and blocked by age and assigned to either a 6 L/d maximum daily milk replacer (MR) allowance (LMR) or a maximum MR allowance of 8 L/d (HMR). Calves were kept in individual hutches until 52 d of age and then moved into pens, forming groups of 10. All calves had ad libitum access to a mash starter feed. Calves in both treatments received the MR distributed in 3 separate allotments between 1 wk after the beginning of the study and 52 d of age. Then, all calves were moved to group pens and preweaned by offering 2 L/calf of the same MR twice daily in a trough until the age of 59 d, when MR offer was further reduced to a single dose of 2 L until the age of 73 d, when all calves were completely weaned. Individual starter feed and MR consumption was recorded on a daily basis until 52 d of age, and on a group basis until weaning time. Body weight was measured at the beginning of the study and at 52 (preweaning), 73 (weaning), and 110, 160, and 228 d of age. Solid feed consumption (mean ± SE) was greater in LMR (821±42.1 g/d) than in HMR calves (462±42.1 g/d) between 42 d of age and 52 d (preweaning). As expected, as age increased, solid feed consumption increased, and LMR showed a more marked increase than HMR calves. Despite the greater solid feed intake of LMR calves, HMR grew faster than LMR calves until preweaning time, but from preweaning to weaning, LMR calves grew more than HMR calves (977 vs. 857±30.7 g/d, respectively; mean ± SE). No differences in feed efficiency were observed. While calves were individually housed, no differences were observed in the incidence of bovine respiratory disease or diarrhea between treatment groups. We concluded that, under the milk regimen, age range of calves, and weaning method used in the current study, before preweaning, HMR calves grow more than LMR calves, but between preweaning and weaning, LMR grow more than HMR calves, overcoming the difference in BW at preweaning. As a result, with the weaning scheme followed herein, providing more milk does not ensure greater performance; no differences are obtained in BW at weaning and at 228 d of life. Also, based on solid feed consumption patterns seen in this study, we determined that the optimum age to reduce MR allowances and foster solid feed intake is around 45 d of age.

A 56-d growth study compared the effects of lasalocid and decoquinate, or a combination of the two, on rate of gain and control of naturally occurring coccidiosis in weaned Holstein calves. Sixty-four calves (mean BW of 188 kg; age 16 wk) were blocked by BW and degree of oocyst shedding and assigned randomly to one of four treatments with 4 calves per pen and 4 pens per treatment. Treatment groups included an unmedicated control group, lasalocid at 1 mg/kg of BW, decoquinate at .5 mg/kg of BW, or lasalocid plus decoquinate. For the combination treatment, decoquinate was fed at the recommended rate for 28 d, followed by lasalocid for the remaining 28 d of the study. Diets were based on dry-rolled corn and haylage and were fed once daily for ad libitum feed consumption. Calves were weighed weekly, and feces were collected for quantitation of oocyst shedding. Oocyst shedding was low, and clinical coccidiosis was not observed. However, unmedicated calves shed oocysts at a higher rate than medicated calves. Small differences were found among treatments on overall rate of gain and gain efficiency. There was little advantage in gain or performance when calves with subclinical coccidiosis were medicated with anticoccidial agents.

Diets containing soybeans roasted at different temperatures were fed to investigate effects on growth and feed consumption by calves. In trial 1, Holstein calves (n = 71) were used from birth to 10 wk of age. Three of the diets contained 18% CP and soybeans roasted to achieve exit temperatures of 99, 127, or 143°C and air cooled immediately after they exited the roaster; the fourth diet contained 15% CP and soybeans roasted at 127°C. Calves fed the diet containing soybeans roasted at 143°C consumed more feed, gained mote BW, and were more efficient in converting feed and energy to gain than those fed soybeans roasted at 99 or 127°C. Performance was intermediate by calves fed the diet containing 15% CP. In the second trial, 84 Holstein calves were used from 0 to 8 wk of age and were fed diets containing soybeans that had been roasted to achieve exit temperatures of 132, 146, or 163°C, followed by 30min of steeping. performance of calves fed soybeans processed at 146°C was superior to that of calves fed soybeans processed at 132 or 163°C. Rumen-undegradable intake protein, determined by a protease method, increased with increasing roasting temperature, but unavailable protein, as calculated from ADIN, was high for soybeans roasted at 163°C. Lipase activity decreased with increasing roasting temperature and was absent for soybeans toasted at 163°C. Roasting temperatures that resulted in superior calf performance corresponded to corrected undegradable intake protein (undegradable intake protein minus indigestible intake protein) of 50 to 60% and a trace of lipase activity.

Growth, age at weaning, fecal scores, and blood metabolites of young dairy calves were measured to determine the most effective method of lasalocid administration. Forty Holstein bull calves were blocked by date of birth and assigned randomly to one of four treatment groups: no lasalocid; lasalocid in starter; lasalocid in prestarter and starter; or lasalocid in milk, prestarter, and starter for a 12-wk period. Calves were fed milk twice daily until they consumed 227 g/d of prestarter, at which time the p.m. milk feeding was discontinued, and starter was offered for ad libitum intake as a mixture with the 227 g/d of prestarter. When total dry feed consumption reached 1.3% of birth weight, the calf was weaned. When the calf was 5 wk of age, the prestarter was discontinued. Daily gain tended to be greatest during the first 6 wk for the calves receiving lasalocid in milk, prestarter, and starter. These calves also were weaned with less variation in days to weaning. By wk 8 through 12, there were no differences in gain among the treatment groups.

Eighty female Holstein calves were used to examine the effects of high amounts of added dietary Fe as ferrous carbonate on performance of young dairy animals. Experimental starters containing either 0, 500, 1000, 2000, or 4000 ppm supplemental Fe as ferrous carbonate were fed for 8 wk beginning at 1 wk of age. The control starter contained 170 ppm Fe, all of which came from the major feed ingredients. The calves were fed limited amounts of whole milk for the first 5 wk. Weight gains and feed consumption were not consistently reduced at the higher amounts of supplemental Fe, but the lowest average values were at 2000 ppm added Fe. However, during wk 7 and 8, when no milk was fed, calves fed 2000 or 4000 ppm had reduced feed intakes and weight gains. Feed efficiency and health of the calves were not affected by supplemental Fe. The results of this study indicate that the performance of calves was not affected appreciably by 4000 ppm supplemental Fe as ferrous carbonate from a pure lenses of siderite ore. This is a higher tolerance than shown previously for ferrous sulfate Fe.

The objective of this study was to develop and validate a computerized system to monitor feeding behavior and feed intake of loose-housed dairy cattle. The system consisted of 28 scales located in front of each self-locking place of a regular feedbunk. All cows had access to all scales indifferently. Each visit to the feedbunk was monitored by a transponder in the ear of each cow that was detected by a proximity reader located at the top right corner of each headlock. The data from the scales and the proximity readers were continuously recorded by a computer with an average scanning time of 3.5 s. The monitoring system was validated using all 28 feeding places and 51 lactating cows in a series of 4-h observations during 5 different d. During the observation periods, for each feeder, 2 observers recorded the cow number and the exact time of the visit. The observed data were then compared with the computer records. To validate the ability of the system to monitor feed consumption, on separate days, the amount of feed consumed by a cow during a visit was also measured manually with an external scale, and the feed that disappeared from each scale in 2 different 24-h periods was compared with the sum of feed consumed in each scale during these 2 periods. The average time spent in a given scale by each cow determined by direct observations was similar to that determined by the computer. The system was accurate and showed a high specificity (98.8%) and sensitivity (99.6%) for cow detections. Feed weights determined by the computer system were similar to those measured manually with an external scale, implying that the system was also accurate in measuring individual intake weights. In conclusion, the system provided a reasonable estimate of the number of visits per animal, length of each visit, amount of feed consumed per visit and animal, the total amount of feed consumed daily by each animal, and the rate at which animals consume feed.

Based on results from previous 14-d sequential elimination trials, which indicated that cows in early lactation preferred a sucrose-sweetened diet, a 12-wk lactation trial was conducted to evaluate further the effects of sucrose supplementation. Twenty-four cows (16 multiparous Jerseys and 8 primiparous Holsteins) were assigned at parturition to a control or sucrose-sweetened (1.5% of dietary DM) TMR in a randomized complete block design. The diet included 10% corn silage, 30% alfalfa haylage, and 60% concentrate based on corn and soybean meal on a DM basis and was fed to ensure 10% orts. An additional 2.3 kg of alfalfa hay were fed for the first 5 d postpartum. Covariant-adjusted (BW on the day of parturition) mean DMI, milk yields, 3.5% FCM yields, and percentages of milk fat, milk protein, and SNF were unaffected by treatment and averaged 19.0 and 19.1 kg/d, 28.4 and 29.3 kg/d. 28.4 and 28.4 kg/d, and 3.40 and 3.30%, 3.51 and 3.28%, and 8.4 and 8.3%, respectively, for cows on control and sucrose-supplemented diets. In the absence of a choice of diets, sucrose at 1.5% of dietary DM did not enhance mean DMI over the first 12 wk postpartum; however, a transient increase in consumption of the sucrose-supplemented diet may have occurred over the a 2-wk period after parturition. Variation in feed consumption during early lactation suggests that additional data are needed to examine this potential effect.

Eight neonatal bull calves were rumen fistulated and assigned to one of two weaning programs to study the effect of diet and weaning age on ruminal metabolic development. All calves were fed colostrum until 3 d of age and milk until weaning. Calves in the early weaning program were fed milk and a highly palatable, prestarter diet until they consumed 227 g/d and then a mixture of 227g of prestarter and all the starter diet they would eat. Calves in this group were weaned at 4 wk of age. Calves in the conventional weaning program were fed milk and a starter diet and weaned at 6 wk of age. Eight ruminal samples were collected over 12h from each calf at 1, 4, 8, and 12 wk of age. Ruminal fluid samples were analyzed for pH, VFA, NH 3 N, and L(+)- lactate and D(−)-lactate concentrations. Calves weaned early had lower ruminal pH, higher total VFA concentration, and higher molar proportion of butyrate than conventionally weaned calves. Ruminal NH 3 N and lactate concentrations were not significantly affected by the weaning program, although lactate tended to be higher in calves weaned early. Ruminal VFA concentration increased and NH 3 N concentration decreased with increased feed consumption by calves in both groups. Molar proportions of acetate, isobutyrate, and isovalerate decreased, and those of propionate increased with age in both groups. Apparently, ruminal metabolic development, as evidenced by changes in fermentation products, was faster in calves weaned early than in calves weaned conventionally.

Seventy-seven Holstein calves born during October through March were used to evaluate increased solids intake from liquid feed and once versus twice daily feeding on weight gains and health of calves. Dietary treatments were 3.6 kg whole milk fed once daily (A) or in two feedings (B), 3.6 kg whole milk plus 113 g whey-fat blend powder fed once daily (C) or in two feedings (D), and 4.5 kg milk daily fed in two feedings (E). Calves fed diets A and B received .45 kg of solids daily in their liquid feed, whereas those fed diets C, D, and E received .56 kg of solids. These amounts were fed for 4 wk starting 3 d after birth, then amounts were reduced by half during the 5th wk. Weight gains during wk 1 to 5 (.36, .47, .48, .57, and .61 kg/d) were highest for calves fed additional solids and were greater when fed liquid twice instead of once daily. Weight gains were similar for all calves during wk 6 to 10, although weight gains during the entire 10 wk (.67, .70, .72, .81, and .82 kg/d) reflected the differences of the initial 5 wk. Dry feed consumption was similar for all treatment groups during all periods. Incidence of diarrhea tended to be lower in calves fed twice daily, although diarrhea was not a major problem for any treatment group. For optimum growth and health, calves housed in hutches during cold weather should be fed at least .56 kg of solids daily in two or more liquid feedings.

A feed flavor was added to milk and to starter to determine if young calves could be encouraged to eat dry feed by association of starter and milk. Forty-eight calves received milk until weaning at 5 wk of age. Twenty-four of the calves received a commercial flavor containing ethyl butyrate, butterscotch and maple flavors, and saccharin at 137 mg/kg added to milk just before feeding. Within each group, 12 of the calves were fed a pelleted starter; the other 12 were fed the same starter with the same flavor added at 6 g/kg. Beginning with wk 2, calves fed flavor in starter began to consume more starter than those consuming starter without flavor; this difference was significant in wk 5. Calves fed flavor in milk and starter consumed more starter than calves not fed flavor from either source. Calves receiving flavor in starter gained more weight than those not fed flavor. Weight gains of calves fed flavor in starter were similar regardless of whether they were fed flavor in milk. Flavor in milk without flavor in starter had no significant effect.

A dynamic model that simulates change was constructed by combining detailed information on biological and economic characteristics of the dairy cow. This model can be utilized to study strategies of dairy management, particularly for situations where collection of empirical data is difficult. The GASP IV simulation package allowed simulation of both discrete (time-oriented) events such as freshening and breeding as well as continuous processes such as milk production and feed consumption. Because the initial question is concerned with the relationship between herd life and profitability of the cow, the model contains detailed estimates of relationships between age, production, and costs of production. The model has a flexible modular organization that can be adapted to numerous management options. For basal case validation, driving (control) variables were input descriptive of a commercial dairy herd. Response variables were compared to survey information from dairy farms in the Northeast.

To evaluate utilization of processed whole soybeans by calves, in the first trial raw soybeans and soybeans processed at 138°C without tempering or 138°C with tempering, or at 171°C were evaluated in a nitrogen balance trial of four male Holstein calves 10 to 15 wk of age. Nitrogen retention was similar when calves consumed any of the heat-treated soybean diets but less for the raw soybean diet. In the second trial raw and processed soybeans were evaluated in an 8-wk growth trial of 96 Holstein day-old calves. Starters contained soybean meal, that with added fat, raw soybeans, or soybeans processed at 138, 171, or 191°C in a California Pellet Mill Jet-Sploder. Calves consuming the starters containing soybeans processed at 171°C consumed more feed, gained faster, had lower fecal scores (less scours), and less mortality.

Rations containing finely ground air-dry and reconstituted (70% dry matter) sorghum grain were compared in a switchback trial with 21 lactating dairy cows. Feed consumption was ad libitum with the restriction that grain concentrates comprise no more than 60% of the total intake of dry matter. Reconstituted grain was consumed more readily than ground grain, resulting in a higher percentage of concentrates in rations of cows fed reconstituted grain than of control cows (55.8 versus 52.8%). Milk yield and composition were similar for cows on the two treatments. Apparent digestibility of ration components and gross efficiency of feed utilization were not affected by method of grain processing. Reconstituted sorghum grain and finely ground grain on a dry basis were equal in feeding value for high producing dairy cows.

Eight Holstein cows were assigned to two groups of four each, and a switchback design was used. Treatments were 4 mA of alternating current and no current. Four periods were each 96 h. Current was applied across subdermal electrodes, located on each cow's spine for 30 s, with a 30-s rest period between exposures for 5 min. Cows received current every 4 h for four 24-h intervals. No individual cow received current at the same time every day. Milk yield was reduced .16 kg/milking by exposure to 4 mA current. This decrease was not statistically significant. Percent milk fat and milk protein were not changed by current. Overall numbers of milk somatic cells were variable during the experiment. They increased during exposure to current, yet the increase was not statistically significant. Overall mean feed consumption and water consumption were not affected by treatments. The greatest behavioral response to current was upon initial exposure. Cows became accustomed to shock within 24 h of exposure. By the end of the fourth 96-h period of exposure, behavioral responses to current were almost extinct. We conclude that exposing cows to 4 mA of alternating current, in a semirandomized nonavoidance environment, for four consecutive 24-h intervals does not alter milk yield, milk composition, or intake of feed and water.

The toxicity of DL -methionine and methionine hydroxy analog infused into the rumen or abomasum was gauged by relative feed consumption. A continuous intraruminal infusion of at least 3 days' duration of DL -methionine equivalent to about 2.5% or more of dietary dry matter intake was required to reach a toxic amount. This was approximately four times the amount necessary when it was infused into the abomasum. Methionine hydroxy analog equivalent to about 1% or more of dietary dry matter intake was toxic when infused into either rumen or abomasum. This is in large excess of suggested amounts of analog supplementation. Reduced palatability is likely to occur in advance of reduced intake due to toxicity.

Water intake, milk yield, feed consumption, and milk composition of lactating cows were monitored before, during, and after 21-d exposures to voltage. Fifteen first parity and 15 multiparous cows were divided equally among five treatments (0, .5, 1, 2, and 4 V) in which voltages were applied continuously between water bowls and metal floor mats. Initial application of voltage caused delays in drinking, which increased with voltage. Two animals receiving 4 V did not drink for 36 h, at which time their voltages were disconnected. All other animals drank within 36 h and showed no significant long-term difference in the monitored parameters. Drinking behavior in the presence of voltage was investigated further by exposing 44 first parity and 40 multiparous cows to voltage (3, 4, 5, or 6 V) for 2 d. Four first parity cows receiving 5 or 6 V did not drink for 36 h while all other animals did. Delays in resumption of drinking increased with voltage. In total, all 42 animals exposed to 3 V or less adapted within 36 h, as did 60 of the 66 Holsteins (91%) exposed to 4 to 6 V. Adaptation may have been enhanced by the continuous presence of the voltages.

The amount of α-glucose polymers entering the duodenum of re-entrant cannulated steers was measured. In each of two trials, four steers received 275g or 500g of a high-grain diet every 2h; 16 and 12 total duodenal digesta, 8-h collections were made. The mean flows of digesta were 976 and 1,685 ml/h, and dry matters of duodenal digesta were 4.8 and 5.8% when animals were given 275 and 500g of feed. About 58 to 60% of consumed dry matter was digested and absorbed before reaching the duodenum at both intakes. Glucose in duodenal digesta, as a percentage of that ingested, was 3.6 and 5.2, and total glucose recovered in duodenal digesta per 8-h collection averaged 20 and 40g during low and high feed consumption. If all the glucose (60 g/day) passing to the duodenum during 275g feed intake were absorbed, it would contribute only 9% of the total glucose metabolized by these animals.

Feed intakes, weight changes, and behavioral activity of heifers on either an electronically controlled or tie-stall feeding system were compared in two trials with 16 heifers in each trial. Eight heifers per trial were fed individually by one of the two systems. Trial 1 was for 6 wk; trial 2 for 18 wk. Behavioral activity was observed directly and by closed circuit television. Daily intakes of feed were not different for heifers on electronic doors from those on tie-stall feeding during trial 1. During trial 2 heifers on a switchback experiment consumed more feeding with electronic doors than on tie-stall feeding (10.8 versus 9.9 kg daily). A large interaction of group by treatment indicated higher intake by some heifers on tie-stall feeding. Average daily gain was not measured during trial 1 but was .49 kg for heifers on electronic feeding and .67 in tie stalls during trial 2. The correlation between average daily gain and feed consumption was −.18. Heifers fed electronically spent more time feeding and standing but less time lying down than heifers on tie-stall feeding during trial 1. Television surveillance of heifers on electronic control during trial 2 revealed considerable individuality in feeding habits. Heifers ate alone 47% of the observed feeding time. Feeding with electronic doors can be a useful innovation with monitoring and repair.

Diurnal changes in percents of inorganic phosphorus in plasma were measured in three Holstein cows fitted with indwelling jugular catheters. Blood was sampled 34 times over 48 h. Changes of inorganic phosphorus of blood plasma appeared to be related to patterns of feed consumption. In a second experiment, effects of diet, season of calving, stage of lactation, lactation number, and milk yield on inorganic phosphorus of plasma and milk were measured with 40 Holstein cows. Dietary treatments were 1.0% calcium, .31% phosphorus; 1.0% and .54%; 1.8% and .30%; 1.7% and .54%. Blood and milk samples were taken at wk 6 postpartum and every 5th wk thereafter. Inorganic phosphorus in plasma and milk was higher for cows in first lactation than multiparous cows. Cows which calved in November to December had the highest inorganic phosphorus in plasma but the lowest in milk. Month of year affected inorganic phosphorus in milk but not in plasma. Inorganic phosphorus in plasma increased as milk yields decreased and as inorganic phosphorus in milk decreased. Dietary phosphorus affected inorganic phosphorus in plasma but not in milk. The correlation between inorganic phosphorus in milk and plasma was -.15. These data indicate the limitations of using inorganic phosphorus in plasma or milk as sole or primary means of determining nutritional phosphorus status of lactating cows.

Sixty young Holstein calves were fed five diets containing various amounts of rye grain up to 18 wk of age. Average daily gain and feed consumption were similar during the first 6 wk; however, calves receiving 60% rye consumed less feed and gained slower than the barley control and 80% roasted rye fed groups in the next 12 wk. Ratios of feed to gain were not different among the five treatments. Apparent digestibilities of the calf diets measured at 10 wk of age were not different; however, calves fed 60 and 80% rye diets tended to show lower digestibilities than the barley control group. Roasting of rye improved digestibilities of acid-detergent fiber and ether extract but slightly reduced protein digestion. Twelve lactating Holstein cows were fed four diets containing 0, 25, 50, and 75% rolled rye in the grain mixtures and grass silage in a switch back design. Grass silage and grain mixtures were offered separately in a 40:60 ratio (dry matter) twice daily but free choice. Replacement of barley with rye in the grain mixtures reduced the total dry matter intake by lactating cows with little effect on average daily milk production, milk composition, and milk prolactin.

Data on 3957 heifers from the Holstein H line, Ayrshire-based A line, and C line (crossbreds between H and A lines) were used. Growth, feed consumption, and feed efficiency from 26 to 34 wk were examined. The full model included the fixed effects of herd, year of birth, season of birth, and additive, maternal, and heterotic genetic effects with 26-wk weight as a covariate. Heterotic and maternal effects were not significant. Adjusted for the 26-wk weight covariate, H line heifers gained 3 kg more than A line heifers with C line heifers intermediate. Adjusted for 26 and 34-wk weight covariates, H line heifers ate 2 kg less TDN than A line heifers and, hence, were more efficient. Correlations among traits were estimated using the residual variance-covariance matrix from the full model. Body weight at 34 wk was correlated with 26-wk weight (r = .88) but essentially independent of rate of gain (r = .02). It was correlated with feed consumed (r = .51) and negatively associated with gain/feed consumed (r = -.25). Gain was correlated (r = .84) with gain/feed consumed but mildly so (r = .28) with feed consumed. Feed consumption was negatively correlated (r = -.25) with gain/feed consumed when the 26-wk weight covariate was included but became much larger (r = -.95) when both 26 and 34 wk weight covariates were included. Although genetic differences in feed consumption and feed efficiency of growing heifers exist, these are small and closely associated with weights and weight gains.

Eighteen lactating dairy cows were used in each of two feeding trials to evaluate the effect of different amounts of wheat middlings in the ration on intake and milk yield. Concentrate mixtures containing 0, 20, and 40% and 0, 40, and 60% middlings in two respective trials were calculated to be isocaloric and isonitrogenous. These made up 60% of the total ration with alfalfa hay as the forage component. Samples for ruminal ammonia and blood plasma urea nitrogen were taken 3h after concentrate feeding. Milk yield of cows fed concentrate mixtures containing 20 or 40% middlings was similar to that of cows fed the control ration; however, yield of those fed a concentrate mixture with 60% middlings was decreased. Milk fat percentage was similar for all groups within trials. Concentration of ruminal ammonia was higher in cows fed rations containing middlings, whereas effect on concentration of plasma urea nitrogen was inconsistent. Similar feed consumption for all treatment groups indicated no ration acceptability problems when middlings were as much as 60% of the concentrate mix.

Four ruminally cannulated cows in first lactation (50 days postpartum) were assigned randomly to a 4 × 4 Latin square with the following feeding frequencies of the same total mixed ration: one, two, four, and eight times a day. Dry matter intake, water consumption, and ruminal pH were recorded hourly during 4-d collection (10-d adaptation between periods, Experiment 1). In Experiment 2, 30 animals were blocked by milk production on wk 4 postpartum and assigned to feeding one or four times a day through wk 19 postpartum. Individual feed consumption and milk production were recorded daily. Hourly consumption patterns of dry matter and water were variable over 24 h; once daily feeding tended to be more variable than other frequencies. Cows fed four times a day had higher ruminal liquid dilution rates than those fed eight times; feeding once and twice a day was not different from either. In Experiment 2, frequency of feeding total mixed ration had no significant influence on dry matter intake or milk yield; however, cows fed four times a day exhibited a consistent weekly tendency to be lower in dry matter intake and higher in milk yield than those fed once daily. Efficiency of fat-corrected milk production was slightly higher for cows fed four times than for those fed once daily.

Bioavailability of P from defluorinated phosphate and dicalcium phosphate and the P requirement were studied with 63 male Holstein calves. A P depletion diet containing .08% total P on a dry matter basis was fed to all animals for 4 wk beginning at 6 wk of age and 61kg weight. Calves developed typical signs of P deficiency. The depletion period was followed by a 6-wk experimental period in which the same depletion diet was used as a control. Phosphorus from each of the two sources was added to make diets containing .14, .20, and .32% total P. Source of supplemental P did not affect weight gains, feed consumption, feed efficiency, serum inorganic P, serum alkaline phosphatase, or bone ash. Weight gains, feed intake, feed efficiency, and serum inorganic P were more sensitive measures of dietary P content than were serum alkaline phosphatase or bone ash. Tibia joint ash was a more sensitive measure than tibia shaft ash or rib ash. Growth rate, feed intake, serum inorganic P, and tibia joint ash each increased linearly with increasing dietary P. The data suggest that the P requirement of 2 to 4 mo calves may need to be revised upward.

Thirty-six Holstein dairy calves were observed for 4 mo to determine the effect of three housing systems (group, individual, and isolated) on gain in body weight, feed consumption, age when concentrate eating commenced, daily pattern of activity, reaction to open field test, and social rank. Six calves were assigned to each of the three treatments in two separate trials. Calves were in treatments for approximately 10 wk after which they were weaned and placed together in groups of 13 for 7 additional wk. Order of greatest weight gain over 4 mo was group, individual, and isolated. Group calves gained faster post-weaning than isolated calves. Group calves commenced eating concentrate at an earlier age than calves on the other two treatments, but total feed consumed was not different during the first 10 wk. Isolated calves tended to spend a greater percentage of the time in recumbency. During an open field test isolated calves entered more squares than group or individually reared calves. Group calves were the most vocal. Group calves ranked highest in the social hierarchy in post-weaning groups.

Thirty-two Holstein heifer calves receiving conventional rations were supplemented with 0 (control), 125, 250, or 500 IU of vitamin E/calf per d. The objective was to determine the optimum requirement based on their overall performance from birth to 24 wk of age. Overall weight gains at 24 wk were higher with 125 and 250 IU and intermediate with 500 IU supplementation compared with no supplementation. Total dry feed consumption and fecal scores were similar among treatments. Serum alpha-tocopherol increased with increased supplementation in a quadratic fashion, being almost doubled with 125 IU compared with that of control calves. Serum creatine kinase, glutamic oxalacetic transaminase, and lactic dehydrogenase values in the unsupplemented calves indicated cell membrane damage. Serum glucose was higher at 8 wk in supplemented calves, but no differences among other serum metabolites were observed. Hematological responses at 4 and 8 wk of age indicated lower mean corpuscular hemoglobin in calves given 500 IU than others and lower mean corpuscular hemoglobin concentration in calves given 500 IU than in calves given 125 or 250 IU. We conclude that supplementation of conventional rations with 125 to 250 IU vitamin E/animal per d can increase the performance of calves.

Effects of mild and severe hypervitaminosis A on retinol transport and clearance were studied in mature ewes. Excessive vitamin A intake was associated with high concentrations of vitamin A in plasma and liver, with elevated serum enzymes, with decreased feed consumption and packed cell volume, and with epithelial hypcrplasia. Retinol transport in plasma increased 6- to 8-fold with excessive dietary vitamin A, was greater with mild hypervitaminosis A, and increased exponentially with vitamin A concentration in plasma. Clearance of retinol from plasma increased 2-fold with hypervitaminosis A, exhibited a greater response in the mild group, and increased linearly with vitamin A concentration in plasma. The relationship of clearance to vitamin A concentration in liver was described best by a power function. Retinol clearance represents a mechanism to maintain vitamin A concentration in plasma and may be most effective below vitamin A concentrations of 135 μ g/dl plasma. With severe hypervitaminosis A, massive vitamin A accumulates in liver leading to hepatic dysfunction and a resultant decrease in retinol clearance from plasma.

Production of milk, solids-not-fat, fat-corrected milk, milk fat, and milk protein were lower for cows on sainfoin hay than for those fed alfalfa hay in two switch-back trials. Hay and grain consumption did not differ for cows receiving the different hays. In a palatability study, 6-mo old heifers preferred sainfoin hay to alfalfa hay. Metabolism studies with mature rams gave digestible coefficients (%) of 65, 63.3, 59.2, 31.6, and 85.5 for dry matter, protein, ether extract, crude fiber, and nitrogen free extract portions of sainfoin hay. Digestibilities with steers were (%) 59.6, 44.9, 67.4, 35.1, and 72.9. Average daily gain and feed consumption did not differ for 319 kg heifers full-fed either sainfoin or alfalfa hay for 60 days.

Mature rats were fed a diet containing 5 μg/g DDT for 14 days. The inclusion of 5% activated carbon with DDT reduced DDT retention (P < 0.01). When DDT feeding was followed by 14 days of activated carbon feeding the retention of DDT was 62.4 for the control and 62.6% for the treated group. Activated carbon had no effect on feed intake but significantly reduced the 14-day weight gains from 10.2 to 3.6 g (P < 0.05). Four of 8 cows previously contaminated with dieldrin, DDD and DDT were fed 1 kg/day activated carbon for 14 days. There were no significant effects on the pesticide concentrations in the milk fat. The activated carbon resulted in nonsignificant reductions in milk (17.8 to 16.3 kg/day) and fat (.84 to .77 kg/day) production. In a second experiment 4 of 8 cows previously contaminated with dieldrin, DDE and DDT were fed 1 kg/day activated carbon for 26 days. The activated carbon had no significant effect on the milk and body fat concentrations of the pesticides. Milk production (20.4 to 18.5 kg/day) and fat production (0.82 to 0.72 kg/day) were reduced (P < 0.05) by the activated carbon. Activated carbon had no effect on feed consumption.

In a feed preference or acceptability trial 12 dairy calves offered a choice of a complete starter (18% crude protein and 20% ground suncured alfalfa) with 0 or 0.2% monosodium glutamate and weaned at three weeks, consumed more 0.2% glutamate starter each week and cumulatively from three to nine weeks of age than they did starter without glutamate. Differences in weekly starter consumption were significant (P In a growth trial 10 calves weaned at four weeks and fed 0.2% glutamate starter ate slightly, but not significantly (P>0.05), more feed weekly from birth to six weeks than 10 calves fed the same starter without glutamate. Slight differences in starter consumption from birth to four weeks were reflected in less weight loss the week after weaning by calves eating the glutamate ration than by those receiving the control starter. Differences in daily gain and feed efficiency from glutamate in the starter were negligible.

Summary In a growth experiment with seven calves per starter, the addition of 10% brown grease, 10% hydrogenated cottonseed oil, or 5% of each to calf starters markedly reduced consumption and weight gain. The addition of 10% of each of the fats further reduced weight gains and starter consumption. The simple and partial correlations between starter consumption and weight gains were 0.84 and 0.85, which indicates that a major portion of the reduction in growth was associated with reduced starter intake. In a cafeteria study, each of nine calves significantly preferred the control starter. However, one calf demonstrated a similar decisive preference for the starter with 10% added brown grease. In another cafeteria study with 11 calves, 1% brown grease did not significantly affect palatability of a calf starter.

Summary In an experiment utilizing 39, three-day-old Holstein and Jersey calves, results indicate that calves can be weaned successfully from milk at 24 days of age. All calves were coaxed to eat starter prior to weaning, and all made acceptable growth rates. The addition of dried skimmilk provided little additional benefit over a vegetable source of protein in the starter of early weaned calves. There was no statistical difference between the starters for calf growth rate, feed consumption, or efficiency values. Calves on Starter I, which contained dried skimmilk, had significantly higher coefficients of apparent digestibility of dry matter, but no significant difference was encountered for crude protein digestibility or TDN values between the starters.

Summary In four successive trials, weight gain was observed on growing Holstein heifers as a result of feeding 24×or 10×vs. 2×daily. Both restricted and unrestricted systems for governing feed intake were employed. Frequent feeding induced faster weight gain only when the rations were quantitatively restricted, and only for a period of 30 to 38 days. There were no significant differences in feed consumption between treatment and control animals.

Forty-eight Holstein calves were assigned at birth to one of three calf starter treatments to 1) compare the acceptability (palatability) and nutritive value of starters containing principally barley and cottonseed oil meal, prepared as pellets or mash, and a pelleted commercial starter containing a complexity of protein sources, vitamins, and minerals; 2) observe growth rate and feed utilization on the different starters; 3) determine daily feed consumption when starters and hay are fed ad libitum; and 4) compare the TDN values of the starters as well as utilization of absorbed nitrogen. Calves consuming the simple starter, as either mash or pellets, consumed more starter (P

Summary Young Jersey calves whose rations were supplemented with orotic acid and methionine gained 46% more in body weight than did comparable controls. A 41% superiority in efficiency of feed utilization also was observed in the treated group. Both observations are statistically significant at P = 0.01. No significant difference was found in increased height at withers.

Summary A series of three experiments comparing the feeding value of different concentrate mixtures indicated that there was little or no difference in the palatability of concentrate mixtures that differed widely in the ingredients used. A mixture containing 76 per cent of farm-grown grains was equal in promoting milk production and in palatability to a standard concentrate mixture throughout a continuous study of 26 weeks' duration. Similar results were obtained in a double reversal trial. Another experiment involving four concentrate mixtures containing widely different ingredients showed there was little difference in feeding value among the four mixtures. Abrupt changes from one mixture to another had no unfavorable effect on feed consumption. All mixtures proved equally palatable. Body weight essentially was unaffected by the different concentrate mixtures.

Summary The dairyman may use commercial milk replacers or feeds containing antibiotic or may add antibiotic separately to milk or other feeds used in calf raising. This experiment was to determine the effects of feeding 50mg per day of antibiotic in milk, 25mg per pound of starter, or these concentrations in both milk and starter. Thirty calves were reared to 16 wk on each of the three treatments and compared to a control group of 30 calves not fed antibiotic. During the first 8 wk, the calves fed antibiotic in the milk grew significantly faster and ate significantly more feed than those in the control and starter-supplemented groups. Those receiving antibiotic in the starter alone gained significantly more than the controls, and those fed antibiotic in both milk and starter gained slightly more than those with antibiotic only from milk. Antibiotic feeding did not reduce calf mortality or significantly prevent diarrhea. From 8 to 16 wk antibiotic feeding in starter produced slightly greater weight gains and feed consumption, but the differences were not significant statistically. These results indicate that the most effective method of feeding calves antibiotic is in milk and, that after weaning, the effects of antibiotic feeding are of small importance.

Summary Fifteen Holstein bull calves were fed a semipractical type diet containing 8.6 ppm of zinc on an as-fed basis until 29 wk of age. Following this depletion phase, they were fed the same basal diet with the addition of various levels of zinc for 8 wk. As indicated by weight gains, feed consumption, testicle size and weight, testicle zinc content, blood zinc content, blood carbonic anhydrase activity, and clinical examination, calves fed the basal ration performed as well as those fed supplemental zinc. It was concluded that, under the conditions of this experiment, calves do not require more than 8.6 ppm of zinc in their diet for normal performance to nine months of age.

Milk production, feed consumption, and feed efficiency data were collected on 425 first lactation cows by 31 sires to determine if a part-lactation measure of feed efficiency would effectively predict total lactation efficiency. The data were summarized by ten 30 day periods (1 to 30, 31 to 60…, 271 to 300), and a 300-day lactation total basis. Three periods (two, five, and seven) were examined to estimate heritabilities and genetic correlations. Phenotypic correlations among measures of feed efficiency in adjacent periods ranged from .82 to .88. Correlations between the 10 part-lactation measures and total ranged from .64 to .87 with the highest occurring in Periods 4 and 5. The highest phenotypic correlation between part-lactation efficiency and total fat-corrected milk yield occurred during Period 5 (.72). Correlations between feed consumed in each of the 10 periods and total fat-corrected milk and total efficiency ranged from .10 to .69 and −.29 to .32. The highest genetic correlation of the three part-lactation efficiency measures with total occurred during the fifth period (1.00). The genetic correlation between fifth period efficiency and total fat-corrected milk yield was higher (.91) than the other two part-lactation measures but similar to that for total (.93). Heritabilities of the three part-lactation measures of feed efficiency were .44, .44, and .34 as compared to .56 for total lactation efficiency. Selection for efficiency during Period 5 would be 89% as effective as direct selection for total efficiency. Selection for yield during Period 5 would improve efficiency in the same period more rapidly than direct selection

Summary Thirty-five Holstein and Jersey calves were fed starters containing five, nine, or 13% crude fiber, with the fiber of the higher levels coming from either corn cobs and shucks or alfalfa meal. There were no important differences among the calves owing to level or source of crude fiber, in weight gain, starter consumption, or hay consumption, at either eight or 16 weeks (P = 0.05). Highly significant simple correlation and regression coefficients were observed at 16 weeks of age, between starter consumption and gain (r = 0.86) (b = 0.37-lb.) and between starter consumption and hay consumption (r = −0.55) (b = −0.59-lb.). Highly significant partial correlation and regression coefficients were observed between starter consumption and gain and between hay consumption and gain.