Economic viability of crosses of Bos taurus and Bos indicus for dairying in warm climates.

Countries in the warm climatic zones need greater domestic supplies of milk. To increase yields, the option that is least expensive and most widely used is to cross dairy breed sires with local cattle. First generation crosses have more vigor than other crosses under stressful environmental conditions; growth rate, milk yield, and reproduction rate exceed those of local breeds and other crossbred combinations. On average, lactating first generation crosses are fed energy at 45 to 60% below their potential response, which limits their capabilities. Other crosses with local breeds fall short of first generation crosses as do some of the present synthetic breeds with 5/8 to 3/4 dairy breeding. Well-fed (> 2.5 maintenance needs) Holstein or Jersey crosses containing 1/4, 1/2, or 3/4 Bos indicus (Zebu) tend to follow projections of parental means for milk yield, reproduction rate, and tolerance to heat stress; however, for crosses, losses exceed predictions for lactation length, persistency of milk yield, feed efficiency, and rate of milking. Size of thoracic and abdominal organs, size of endocrine glands, stomach weight, and intestine length are lower than expected compared with values for purebreds. The smaller digestive system affects feeding intake of B. indicus crosses, and the smaller endocrine glands appear to limit responses to high energy diets. Possible directional dominance of B. indicus needs further investigation. The first generation crosses could support their use for dairy purposes if feeding rate and management were optimal, but prospects for other crosses remain questionable.

Genetic methods of improving dairy cattle for the south: a review and prospects from Regional Project S-49.

Objectives of Southern Regional Research Project S-49, comprising eight contributing experiment stations, are to determine direct response to selection in milk and the resultant correlated responses in nonyield traits, to define and evaluate selection criteria for total economic merit or profit, to quantify genetic and environmental components of underlying physiological characters responsible for genetic gains in economically important traits, to determine interactions of genotype by environment, and to estimate genetic values for males and females. More than 150 scientific articles from S-49 have been published in journals from 1975 to 1985. These results have contributed in a major way in identifying issues and understanding the genetic control of cow performance and economics of genetic improvement programs.

Genetic evaluation of Holsteins in Colombia.

Original data consisted of 31,777 records of progeny of 1442 sires for calvings between 1975 and 1983. Unadjusted means for milk yield (kg), days in milk, days dry, calving interval, days carried calf, and age at calving were 4281, 267, 88, 421, 145, and 36.6. Estimated total variance for first lactation milk yield by Henderson's method 3 was 1,385,436 kg2 with sire and error variances accounting for 1.8 and 98.2%. Heritabilities for milk yield, lactation length, age at calving, and days carried calf were .07, .06, 2.59, and .01. High estimate for age was attributed to confounding of sires with season of calving. Genetic and phenotypic correlations between traits were milk and lactation length, .76 and .72; milk and age at calving, .17 and -.04; milk and days carried calf, -2.11 and .13; lactation length and age at calving, -.13 and -.06; lactation length and days carried calf, .87 and 16.; age at calving and days carried calf, -.60 and -.03. Sires with at least 10 daughters were evaluated by best linear unbiased prediction procedures. First lactation sire values for milk ranged from 359 to -340 kg with an average difference between sires of 12 kg. Sire values using all lactations ranged from 505 to -286 kg with an average difference between sires of 13 kg. Rank correlation between all and first lactation evaluations was .77.

Estimating genetic values for milk production in the tropics.

Variance components and predicted sire values were estimated using 305-d projected and unprojected milk records of varying lengths. Original data consisted of 15,512 lactation records of daughters of 138 Jamaica Hope sires that calved between 1969 and 1981 in 38 commercial dairy herds in Jamaica. Classification of records had little effect on components of variance. Herd-year-season variance decreased from 36% using all lactations to 28% with first lactations only. Sire variance was consistently about 10%. Cow component of variance accounted for 17% of the total variation using all lactations and 36% using all lactations of cows with recorded first lactations. Heritabilities for milk by Henderson's method 1 were five to six times larger than estimated from method 3 due to sire by herd confounding. Predicted sire values were between +400 kg and -400 kg. Rankings of sires with at least 5 progeny were considerably influenced by record classification, especially for sires with highest predicted values. There was less influence on rankings when at least 10 progeny per sire were used while the range in predicted sire values was larger using first lactation records only.

Estimating genetic values for milk production in the tropics

Variance components and predicted sire values were estimated using 305-d projected and unprojected milk records of varying lenghts. Original data consisted of 15,512 lactation records of daughters of 138 Jamaica Hope sires that calved between 1969 and 1981 in 38 commercial dairy herds in Jamaica. Classification of records had little effect on components of variance. Herd-year-season variance decreased from 36 percent using all lactations to 28 percent with first lactations only. Sire variance was consistently about 10 percent. Cow component of variance accounted for 17 percent of the total variation using all lactations and 36 percent using all lactations of cows with recorded first lactations. Heritabilities for milk by Henderson's method 1 were five to six times larger than estimated from method 3 due to sire by herd confounding. Predicted sire values were between +400 kg and -400 kg. Ranking of sires with at least 5 progeny were considerably infleunced by record classification, especially for sires with highest predicted values. There was less infleunce on rankings when at least 10 progeny per sire were used while the range in predicted sire values was larger using first lactation records only (AU)

Growth and reproduction characteristics of purebred and crossbred dairy cattle in first lactation.

Breed additive, maternal, and heterozygotic effects on 11 monthly postpartum body weights, average size, weight gain, age at first calving, and days open were estimated by linear regression analyses from records of 680 purebred and crossbred animals. Calving year, age, and milk yield were significant environmental effects. Positive regressions of age on body weights indicated late calving cows were heaviest postpartum and had most days open. Negative regressions of milk yield on weight gain and postpartum weight showed greatest losses of weight associated with highest yields. There were breed differences in growth; purebreds highest to lowest were Brown Swiss, Holstein, Red Dane, Jersey, and Ayrshire and for weight gain, Brown Swiss, Ayrshire, and for weight gain, Brown Swiss, Ayrshire, Jersey, Holsteins, and Red Dane. Crosses were superior to purebreds in these traits. Additive effects of Holstein were greater than Ayrshire, Jersey, and Red Dane for postpartum body weights and average size. All constants for heterozygotic effect combinations were significant for postpartum weights and average size. Heterozygosity effects increased in magnitude with advancing lactation. Generally, age at first calving and postpartum interval to conception reflected little heterozygotic or maternal effects. There was some indication of breed differences in mean and additive effects for age at first calving.

Crossbreeding in tropical areas with emphasis on milk, health, and fitness.

Although use of European breeds for grading up of local cattle in tropical areas has been underway for nearly one century, few countries have definitive policies on utilization of crossbreeding systems. Crosses with European breeds have excelled local types in age at first calving, milk yield, days in milk, and calving interval. In general, crosses by Holstein sires have proven superior to crosses from other breeds. Contrary to findings in temperature areas, addition of a second improved breed (three-breed cross) has tended to deter rather than to improve performance. The cross 5/8 one breed has performed as well or better than two-breed crosses, but few evaluations have been on farms. The cross 3/4 European usually exceeds the two-breed cross slightly in milk yield, but reproduction is poorer. Mortality losses in 3/4 crosses up to 3 mo often have been high, 14 to 29%. Similarly, experiences with inter se matings of two-breed crosses has proven disappointing. Milk yield of 1/2 crosses of two-breed progeny has been 30 to 60% lower than for first generation two-breed crosses. Numerous attempts have been made to form synthetic groups from crossbred foundation. Most of these gene pools of breed combinations are approximately 5/8 improved breed and 3/8 local. Performance of five synthetic groups and their roles is discussed. Evidence has showed that with high dependence on tropical grasses and crop residues best sustained milk yield is 1800 to 2200 kg of milk per lactation. This means that more attention should be given to breeding plans to raise animal productivity from low to intermediate rather than providing genetic potential for productivity that cannot be supported economically in tropical areas.

Environmental and genetic variation in milk yield of native cattle and crosses with Brown Swiss in India.

Effects of year, season, parity, age, their two-way interactions, lactation length and calving interval on milk yield were investigated utilizing 9,086 lactation records collected from 1930 to 1975 from six breed groups kept in one herd at Karnal, India. The breed groups involved three native breeds (Sahiwal, Red Sindhi and Tharpakar) and three crossbreds with Brown Swiss (F1 crosses between Brown Swiss and three native breeds, inter se crosses, and 3/4 Brown Swiss). Breed, year, season, parity, age and all of the two-way interactions with the exception of breed X season and parity X season were important. Tharpakar produced more milk than Sahiwal and Red Sindhi by 232 and 204 kg. The milk production difference between Sahiwal and Red Sindhi was only 28 kg. The three crossbreds outproduced the purebreds by an average of 766 kg; however, differences in management could have favored crossbreds. Among the crossbreds, F1 crosses were superior. The linear and quadratic regressions on lactation length accounted for 28% of the variation in milk yield after year, season, parity, age and their interactions were absorbed. Calving interval and lactation length together accounted for 29%. Estimates of heritability, from paternal half-sib analyses, and repeatability of milk yield for Red Sindhi, Sahiwal and Tharpakar ranged from .10 to .30. Differences among heritability estimates from different parities were small when more than 500 records were involved.

Crossbred and purebred dairy cattle in warm and cool seasons.

This study was to determine if breed groups ranked differently in warm (May to August) and cool (November to February) seasons of calving and to determine if heterosis was more important in the warm season. A total of 719 records of cows in first lactation in four herds in the southeastern United States were used. Breeds were Holsteins, Brown Swiss, and Jerseys and the crosses among them. Milk and milk fat yields were greater in the cool season than in the warm season. Holsteins exceeded other breeds for milk and milk fat yield in both seasons, but their superiority was less among cows calving from May through August. Days open were longer for Holsteins, particularly in the warm season. In the cool season only the 3/4 Holstein X 1/4 Swiss group exceeded Holsteins for milk, but two groups--1/2 Holsteins X 1/2 Swiss and 5/8 Holstein X 1/4 Swiss-1/8 Jersey--were higher in the warm season. In the cool season three crossbred groups--1) 1/2 Holstein X 1/2 Swiss (Holstein sires), 2) 3/4 Holstein X 1/4 Swiss, and 3) 1/2 Holstein X 1/4 Swiss-1/4 Jersey--had greater milk fat yields than Holsteins, and a fourth--1/2 Holstein X 1/2 Jersey--yielded an equal amount. In the warm season six of the eight crossbred groups had greater milk fat yields than Holsteins. More crossbreds exceeded Holsteins in the warm than in the cool season, suggesting interactions for yields. There was slightly more heterosis in warm than in cool seasons for all traits.

Factors affecting performance of Nili-Ravi buffaloes in Pakistan.

Effects of herd, year, age, season, and lactation length on milk yield and reproductive efficiency for the Nili-Ravi breed of buffalo were determined by analysis of variance of 5,716 lactation records from two herds in Pakistan. Herds differed in all traits. Herd average milk yields were 1,702 and 2,064 kg. Year, season, herd, parity number, days in milk, days open, age, and sire all influenced milk yield. Herd, year, season, and parity number also had significant effects on days open and calving interval. Month of calving was important for time until return to estrus. Percentages of variance in milk yield attributed to herd, year, sire, cow, and residual were 20.3, 11.4, 4.3, 17.0, and 47.0. Classification of lactation length (greater than 60, greater than 250, or at least 305 days) markedly influenced the sire component of variance suggesting some interdependence of milk yield and lactation length. Total variance for milk yield was 466,911 kg2. Within herd heritability for milk yield was .25, and repeatability was low (.31). Predicted breeding values for sires for 250 to 305-day milk ranged from -172 kg to +260. Cows in Herd 1 completed 5.58 lactations with an average herd life of 12.3 yr; Herd 2 cows completed 4.52 lactations with culling at 10.6 yr. Frequency of termination of lactations because of mastitis, reproductive problems, or health was similar to frequencies for cattle. Factors affecting milk yield in buffaloes are similar to those of cattle.

Factors affecting milk fat percent of Nili-Ravi buffaloes in Pakistan.

Monthly fat tests for 895 lactations of Nili-Ravi buffaloes in a Livestock Production Research Institute herd were used to estimate environmental effects on fat percentage. Fat tests rose progressively from 1st to 10th mo of lactation (5.51 to 7.46%). Average lactation fat percent was 6.55 +/- .06. Year effects were significant, but season, age, parity, milk yield, and health status were not. Percent fat increased slightly to maturity (6.54 first parity; 6.65 fifth). Lactations initiated April to September averaged slightly higher (6.60%) than other months (6.50%). There was a slight, although real, decrease in fat percent with increased lactation milk yield (6.60, 6.63, 6.60, 6.43, 6.51 for 1000 to 1500, 1501 to 2000, 2001 to 2500, 2501 to 3000, and greater than 3,000 kg). Effect of treatment for health problems was small (6.51 treated versus 6.59% untreated). Of all fat tests (7,772) 60% were 5.1 to 7.0%, 27% were between 7 and 9%, but only 3% exceeded 9%. Lactation fat percent averaged 1.0 less than most percents for buffaloes because of system of milking and milk yield (2,130 kg). Fat percentage of buffaloes appears to be influenced by environmental factors in the same proportion as for cattle, but buffaloes would be expected to exceed cattle in fat percent by 1 to 3% depending on breed and environmental conditions.

Genetic parameters of body size in purebred and crossbred dairy cattle.

Breed additive, breed maternal, and heterozygotic effects on body weight, height at withers, depth of fore-chest, girth of fore-chest, length from withers to pins, length from withers to hips, and length from hips to pins at 6, 12, 18, and 30 mo of age were estimated from linear regression analyses. Data were available on 87 purebred Ayrshire, Brown Swiss, Holstein, and 213 two-way, three-way, and five-eights crosses. Birth year, birth month, and age of dam were significant environmental effects. Ayrshire additive effects were smaller than Holstein for all traits at all ages except length from hips to pins at 6 and 12 mo of age. Additive effects for Brown Swiss were smaller than for Holstein for body weight at 12 mo, height at withers at all ages, depth of fore-chest and girth of fore-chest at 6, 12, and 18 mo, length from withers to pins and length from withers to hips at 12 and 30 mo, and length from hips to pins at 18 mo. Breed maternal effects were not significant for any trait at any age. Means of crossbreds generally exceeded means of parental breeds, especially body weight. Average heterosis for body weight was 3.0% at 6 mo, 4.6% at 12 mo, 5.0% at 18 mo, and 3.5% at 30 mo of age. Heterosis for weight increased with age through 18 mo and declined by 30 mo of age. Heterosis for other traits was generally 1 to 2% with no trend with age.

Effect of a low chloride diet on lactating Holstein cows.

Twenty primiparous lactating Holstein cows were fed diets supplemented with either .5% sodium chloride or .75% sodium bicarbonate. Those fed the latter diet conserved chloride by reducing the chloride concentration in urine, feces, and, to a small but nonsignificant amount, in milk. The low chloride diet did not affect consumption of feed dry matter and water or milk production and composition. There was no indication of pica or other aberrant taste behavior. One half of the cows in each diet group was given free choice salt block of trace elements. Those fed the low chloride diet consumed more salt (337 versus 149 g/cow per wk). When chloride requirements have been established and data on chloride composition become more widely available, it will be possible to include both sodium and chloride in diet formulations and omit salt. This will reduce the amount of salt needed as either a sodium or chloride supplement.

Use of urea by early postpartum Holstein cows.

Thirty-nine lactating Holstein cows were fed high-energy complete rations ad libitum with crude protein: 1) 11.7% (negative control); 2) 13.9% (1% urea); 3) 16.6% (1% urea); or 4) 16.6% (positive control) in a continuous 12-wk study beginning at wk 5 postpartum. Milk production of 27.7, 31.8, 34.0, and 30.4 kg/day showed the use of urea nitrogen by groups 2 and probably 3. Two digestion-nitrogen balance trials with each cow also provided evidence that urea nitrogen was used for milk secretion. Energy digestibility averaged 59.4, 64.2, 65.4, and 65.8; and lower for the negative control diet. Nitrogen solubility in the diets was 28, 36, 32, and 21%, which reflects the objective of selecting ingredients with low nitrogen solubility for use in urea diets. Concentrations of ammonia nitrogen before and after feeding were 1.1, 3.3, 3.5, 4.2, and 2.2, 11.2, 11.9, and 9.3 mg/100 ml of rumen fluid. The prefeeding amounts were probably too low for maximum microbial growth. Urea-nitrogen concentrations in plasma were 8.65, 10.32, 18.00, and 17.03 mg/100 ml. These results lend support to the postulate that lactating cows in early lactation can use urea nitrogen when high-energy complete rations with ingredients of low nitrogen solubility are fed ad libitum.

Allelic heterogeneity within allozymes separated by electrophoresis in Drosophila pseudoobscura.

Electrophoretic separation of esterase-5 allozymes of Drosophila pseudoobscura in gels of different acrylamide concentrations and in different buffer systems has revealed the existence of six different alleles within the most frequent class, esterase-5(1.00), and three alleles in the other most frequent class, esterase-5(1.07). Two of the alleles affect subunit binding. Esterase-5 allozyme classes based on electrophoresis in 5% acrylamide gels are therefore highly heterogeneous.

External form and internal anatomy of Holsteins and Jerseys.

Body weights, external dimensions, and postmortem measures of internal body dimensions or weights of organs and glands of Holsteins and Jerseys were used to establish norms, interrelationships of traits, and effects of sire and inbreeding on changes in external form. Sires differed in nearly all measures of external body form. Sire effects increased with advancing age whereas effects of inbreeding (greater than 12.5, 3.0 to 12.4, or less than 3.0% of inbreeding) declined. Skeletal dimensions were smallest in the greater than 12.5% inbred group. Differences due to inbreeding were largest at 3 and 6 mo of age and in first lactation. Body heights and head dimensions were nearer to mature size at 3 and 6 mo than other measures. In both breeds, most rapid development was between 3 and 6 mo, but Jersey matured 1 to 2% faster. Age (2 to 3, 4 to 5, 6 to 10, greater than 10 yr) was significant for most postmortem measurements. Correlations among measures of external form were .30 to .93. Correlations between external form and internal features or between internal dimensions and organs were lower. External and internal features were positively correlated, but few external features showed strong enough association with internal features for use as predictors of size of organs, glands, or digestive capacity.