Fertility and survival of pure Holsteins versus crossbreds of Holstein with Normande, Montbeliarde, and Scandinavian Red

First-calf pure Holsteins and Normande/Holstein, Montbeliarde/Holstein, and Scandinavian Red/Holstein crossbreds were compared for days to first breeding, first-service conception rate, days open, and survival. First-calf heifers were in 7 commercial dairies in California and calved from June 2002 to October 2004. Holsteins were required to have a recorded sire with a National Association of American Breeders code to assure they were sired by artificially inseminated bulls. Normande-, Montbeliarde-, and Scandinavian Red-sired crossbreds were all daughters of artificially inseminated bulls via imported semen. For days open, first-calf heifers were required to be at least 250 d in milk and those with greater than 250 d open were truncated to 250 d. Least squares means for days to first breeding were 69 d for Holsteins, 62 d for Normande/Holstein, 65 d for Montbeliarde/Holstein, and 66 d for Scandinavian Red/Holstein crossbreds, and differed significantly from pure Holsteins for Normande/Holstein and Montbeliarde/Holstein crossbreds. First-service conception rates were 22% for Holsteins, 35% for Normande/Holstein, 31% for Montbeliarde/Holstein, and 30% for Scandinavian Red/Holstein crossbreds and, again, differences from Holstein were significant for the Normande/Holstein and Montbeliarde/Holstein crossbreds. Least squares means for days open were 150 ± 4.1 d for pure Holsteins, 123 ± 3.8 d for Normande/Holstein, 131 ± 4.4 d for Montbeliarde/Holstein, and 129 ± 4.6 d for Scandinavian Red/Holstein crossbreds, and all 3 cross-bred groups had significantly fewer days open than pure Holsteins. Three measures of survival were to 30, 150, and 305 d postpartum, and all crossbred groups survived significantly longer than pure Holsteins during first lactation for all 3 measures of survival. Least squares means for survival to 30 d postpartum were significantly different for pure Holsteins (95%) vs. all crossbred groups (98%), were significantly different for survival to 150 d postpartum for pure Holsteins (91%) vs. all crossbred groups (96%), and were significantly different for survival to 305 d postpartum for pure Holsteins (86%) vs. all crossbred groups (92 or 93%).     

Production of pure Holsteins versus crossbreds of Holstein with Normande, Montbeliarde, and Scandinavian Red

Pure Holsteins (n = 380) were compared to Normande/Holstein crossbreds (n = 245), Montbeliarde/Holstein crossbreds (n = 494), and Scandinavian Red/Holstein crossbreds (n = 328) for 305-d milk, fat, and protein production during first lactation. Scandinavian Red was a mixture of Swedish Red and Norwegian Red. Cows were housed at 7 commercial dairies in California and calved from June 2002 to January 2005. All Holstein sires and all Holstein maternal grandsires were required to have a code assigned by the National Association of Animal Breeders to assure they were sired by artificial insemination bulls. Daughters of Normande, Montbeliarde, and Scandinavian Red sires were artificial insemination bulls via imported semen. Best prediction was used to calculate actual production (milk, fat, and protein) for 305-d lactations. Adjustment was made for age at calving and milking frequency, and records less than 305 d were projected to 305 d. Herd-year-season (4-mo seasons) and the genetic level of each cow's Holstein maternal grandsire were included in the model for statistical analysis. Pure Holsteins had significantly higher milk (9,757 kg) and protein (305 kg) production than all crossbred groups, but pure Holsteins (346 kg) were not significantly different from Scandinavian Red/Holstein (340 kg) crossbreds for fat production. Fat plus protein production was used to gauge the overall productivity of pure Holsteins vs. crossbreds. The Scandinavian Red/Holstein (637 kg) crossbreds were not significantly different from the pure Holstein (651 kg) for fat plus protein production; however, the Normande/Holstein (596 kg) and the Montbeliarde/Holstein crossbreds (627 kg) had significantly lower fat plus protein production than pure Holsteins.     

Birth traits of pure Holstein calves versus Montbeliarde-sired crossbred calves

Pure Holstein calves and Montbeliarde-sired crossbred calves from multiparous Holstein dams were compared for gestation length, calf weight at birth, calving difficulty, and stillbirth in 2 research herds of the University of Minnesota. The Montbeliarde-sired calves from multiparous Holstein dams had significantly longer gestation lengths (283.2 d) than Holstein-sired calves from Holstein dams (278.4 d), and Montbeliarde-sired calves from multiparous Holstein dams had significantly greater calf weight at birth (48.3 kg) compared with Holstein-sired calves from Holstein dams (43.3 kg). However, calves sired by Montbeliarde bulls were not significantly different from calves sired by Holstein bulls for calving difficulty and stillbirth. In addition, Jersey × Holstein crossbred cows mated to Montbeliarde artificial insemination (AI) bulls were compared with pure Holstein cows mated to Holstein AI bulls for gestation length, calf weight at birth, calving difficulty, and stillbirth at their first 3 calvings. Gestation length was significantly longer for Jersey × Holstein cows bred to Montbeliarde bulls than for pure Holstein cows bred to Holstein bulls at first calving (280.3 versus 277.7 d) and second and third calving (282.2 versus 278.6 d); however, Jeresy × Holstein cows bred to Montbeliarde AI bulls were not significantly different from pure Holstein cows bred to Holstein AI bulls for calf weight at birth, calving difficulty, and stillbirth at the first 3 calvings.     

Brown Swiss × Holstein crossbreds compared with pure Holsteins for calving traits, body weight, backfat thickness, fertility, and body measurements

Brown Swiss × Holstein crossbred cows and pure Holstein cows were compared in a designed experiment. All cows were housed in a freestall barn at the experimental station of the federal state of Saxony-Anhalt, Germany, and calved from July 2005 to August 2008. Brown Swiss × Holstein crossbred cows were mated to Holstein AI bulls for first calving and mated to Fleckvieh artificial insemination (AI) bulls for second and third calvings. Pure Holstein cows were consistently mated to Holstein AI bulls. At first calving, Holstein-sired calves from Brown Swiss × Holstein crossbred dams (282 d) had longer gestation length than Holstein-sired calves from Holstein dams (280 d). For second and third calvings, gestation length was significantly longer for Fleckvieh-sired calves from Brown Swiss × Holstein crossbred dams (284 d) than for Holstein-sired calves from Holstein dams (278 d). Holstein-sired calves from Brown Swiss × Holstein crossbred dams (43 kg) and Holstein-sired calves from pure Holstein dams (42 kg) were not significantly different for calf weight at birth for first calving. For second and third calvings, Fleckvieh-sired calves from Brown Swiss × Holstein crossbred dams (50 kg) had significantly heavier calf weight at birth than Holstein-sired calves from pure Holstein dams (44 kg). For calving difficulty and stillbirth, Brown Swiss × Holstein crossbred cows were not different from pure Holstein cows at first calving or at second and third calving. Brown Swiss × Holstein crossbred cows (71 d) were not significantly different from pure Holstein cows (75 d) for days to first breeding during first lactation; however, Brown Swiss × Holstein crossbred cows (81 d) had significantly fewer days to first breeding than pure Holstein cows (89 d) during second lactation, and the crossbred cows (85 d) tended to have fewer days to first breeding than pure Holstein cows (92 d) during third lactation. For days open, Brown Swiss × Holstein crossbred cows were not significantly different than pure Holstein cows during any of the first 3 lactations. For body weight, Brown Swiss × Holstein crossbred cows were significantly heavier than pure Holstein cows during first lactation (621 kg versus 594 kg) and second lactation (678 kg versus 656 kg). Also, Brown Swiss × Holstein crossbred cows (18.20 mm) had significantly more backfat thickness than pure Holstein cows (15.81 mm) during first lactation. Brown Swiss × Holstein crossbred cows (48 cm) had significantly greater chest width than pure Holstein cows (46 cm). Furthermore, Brown Swiss × Holstein crossbred cows had significantly longer front heel walls (5.2 cm versus 5.0 cm), significantly longer rear heel walls (4.2 cm versus 4.0 cm), and significantly more depth of the front heel (4.4 cm vs. 4.1 cm) than pure Holstein cows. This study has shown that F₁ of Brown Swiss × Holstein cows are competitive with pure Holstein cows for all traits analyzed here. For fertility, crossbred Brown Swiss × Holstein cows exhibited fewer days to first breeding during second lactation than pure Holstein cows.     

Results of a producer survey regarding crossbreeding on US dairy farms

Comprehensive surveys were sent to 528 US dairy producers who are currently practicing crossbreeding in their herds. Fifty usable surveys were returned, and the resulting data included qualitative responses regarding facilities, milk recording plans, milk pricing, crossbreeding goals, breed selection, advantages, disadvantages, and future plans. Quantitative variables included producer scores on a 1 to 5 scale for questions regarding ability to fit into the free stalls and milking parlor, milk volume, component percentages, involuntary culling rate, conception rate, calving difficulty, calf mortality, and prices for breeding stock, cull cows, market steers, and bull calves. The most common first generation crosses involved Jersey and Brown Swiss bulls mated to Holstein cows, and backcrosses to one of these parental breeds were most common in the next generation. Producers who responded to this survey desired, and indicated that they achieved, improvements in fertility, calving ease, longevity, and component percentages through crossbreeding. Respondents indicated that crosses involving the Jersey and Brown Swiss breeds had a clear advantage in longevity relative to purebred Holsteins, and conception rates for crosses of Jersey or Brown Swiss sires on Holstein cows were similar to the (high) conception rates typically achieved in purebred Jersey matings. Respondents also indicated that milk composition was improved in the crossbred cattle, but producers cited some difficulties in marketing crossbred breeding stock and bull calves, and noted that the lack of uniformity within the milking herd created management challenges. Based on results of this survey, it appears that crossbreeding can improve the health, fertility, longevity, and profitability of commercial dairy cattle. However, further research is needed regarding specific heterosis estimates for functional traits in crosses involving each of the major dairy breeds, and improvements are needed in systems for recording the ancestry and breed composition of crossbred animals.     

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.     

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.     

Birth traits of Holstein calves compared with Holstein,Jersey, Montbéliarde,Normande, and Viking Red-sired crossbred calves

Holstein (HO) calves, 3-breed crossbred calves of Montbéliarde, Viking Red, and HO (MVH), and 3-breed crossbred calves of Normande, Jersey, and Viking Red (NJV) were compared for gestation length (GL), calf weight at birth (CW), calving difficulty (CD), and stillbirth (SB) in 2 research herds at the University of Minnesota. Calves were born from January 2009 to December 2019. For the St. Paul and Morris herds, HO calves (n = 1,121) were compared with MVH calves (n = 1,393) from primiparous and multiparous cows. For the single herd analysis at Morris, HO calves (n = 476), MVH calves (n = 922), and NJV calves (n = 405) were compared from primiparous and multiparous cows. Primiparous and multiparous births were analyzed separately because multiparous cows had multiple births, and CD and SB are likely different traits for primiparous and multiparous cows. Statistical analysis of GL, CW, CD, and SB included fixed effects of sex of calf, herd, breed group of calf, and year-season of calving. For the St. Paul and Morris herds, HO calves from primiparous (278 d) and multiparous (279 d) HO cows had shorter GL compared with MVH calves from primiparous (280 d) and multiparous (282 d) crossbred cows. The HO calves (39.4 and 43.2 kg, respectively) from primiparous and multiparous HO cows had lower CW compared with MVH calves (40.3 and 44.3 kg, respectively) from primiparous and multiparous crossbred cows. Calving difficulty and SB were not different for HO and MVH calves from primiparous and multiparous cows. For the single herd analysis at Morris, HO calves (278 and 279 d, respectively) from primiparous and multiparous HO cows had shorter GL compared with MVH calves (281 and 282 d, respectively) and NJV calves (282 and 282 d, respectively) from primiparous and multiparous crossbred cows. The CW of HO calves (38.6 and 42.0 kg, respectively) from primiparous and multiparous HO cows was lower compared with MVH calves (39.7 and 42.9 kg, respectively), but higher compared with NJV calves (35.1 and 38.0 kg, respectively) from primiparous and multiparous crossbred cows. Calving difficulty and SB did not differ for HO, MVH, and NJV calves from primiparous and multiparous cows. The longer GL for crossbred calves and higher CW for MVH calves did not increase CD and SB for primiparous and multiparous cows. Dairy producers may implement 3-breed rotational crossbreeding systems that include the HO, Jersey, Normande, Montbéliarde, and Viking Red breeds, and some breeds may increase GL and CW without an increase in CD and SB.     

Comparisons of Holsteins with Brown Swiss and Jersey cows on the same farm for age at first calving and first calving interval

Our objective was to evaluate breed differences for heat-stress resistance as reflected by age at first calving and first calving interval. We examined the effect of geographic location and birth season on age at first calving, and geographic location and first calving season on first calving interval on Holsteins and Jerseys, and Holsteins and Brown Swiss located on the same farm. We defined 7 regions within the United States: Northwest, Central north, Northeast, Central, Central south, Southwest, and Southeast, and analyzed 7 individual states: Ohio, Wisconsin, Oregon, California, Arizona, Texas, and Florida. Brown Swiss were older than Holsteins at first calving (833 +/- 2.4 vs. 806 +/- 2.0 d in regions, and 830 +/- 3.1 vs. 803 +/- 2.4 d in states), but Holsteins and Brown Swiss did not differ for first calving interval. Jerseys were younger than Holsteins at first calving and had shorter first calving intervals. In data from individual states, Holsteins housed with Brown Swiss were older at first calving than were Holsteins housed with Jerseys (800 +/- 2.7 vs. 780 +/- 2.5 d). Holsteins housed with one breed or the other were analyzed as a separate data set, and referred to as "type of Holstein." The interaction of "type of Holstein" with first calving season was highly significant for first calving interval. Geographic location and season effects were smaller for Jerseys than for Holsteins; thus, Jerseys showed evidence of heat-stress resistance with respect to Holsteins. Management modified age at first calving in Holsteins to more nearly match that of the other breed. Longer calving intervals might be partly due to voluntary waiting period to breed the cows.     

Production and calving traits of Montbéliarde × Holstein and Viking Red × Holstein cows compared with pure Holstein cows during first lactation in 8 commercial dairy herds

Montbéliarde (MO) × Holstein (HO) and Viking Red (VR) × HO crossbred cows were compared with pure HO cows in 8 large, high-performance dairy herds. All cows were either 2-breed crossbred or pure HO cows that calved for the first time from December 2010 to April 2014. Best Prediction was used to calculate 305-d milk, fat, and protein production, as well as somatic cell score, and 513 MO × HO, 540 VR × HO, and 978 HO cows were analyzed for production in first lactation. Calving difficulty was scored from 1 (no assistance) to 5 (extreme difficulty). The analysis of calving traits included 493 MO × HO, 504 VR × HO, and 971 HO cows at first calving. Age at first calving was similar for breed groups, and the herds calved both crossbred (23.8 mo) and HO (23.9 mo) cows at young ages. The MO × HO crossbred cows had +3% higher production of 305-d fat plus protein production (actual basis, not mature equivalent) than the HO cows, and the VR × HO were similar to the HO cows for fat plus protein production. Breed groups did not differ for SCS during first lactation. The VR-sired 3-breed crossbred calves (from MO × HO dams) were similar to pure HO calves for calving difficulty; however, MO-sired male calves born to VR × HO dams had a mean score that was +0.5 points higher for calving difficulty than pure HO male calves. The 3-breed crossbred calves from both MO × HO (4%) and VR × HO (5%) first-lactation dams had a much lower stillbirth rate compared with pure HO calves (9%) from first-lactation dams.     

Effects of breed and region on longevity traits through five years of age in Brown Swiss, Holstein, and Jersey cows in the United States

The objective of this study was to assess breed, and breed × region interactions for several longevity-related traits, measured up to 5 yr of age in Brown Swiss, Holstein, and Jersey cows in 7 regions of the United States. Data were analyzed using logistic, poisson, and linear models, and survival analyses. The traits were stayability (yes/no survived to 5 yr of age), number of completed lactations, days lived, herd-life, and days in milk (DIM) to 5 yr of age. Probable lifetime DIM were also estimated using data from the first 5 yr of age of the cows. Herd-life was defined as the days lived up to 5 yr of age minus the age at first calving. Days in milk consisted of herd-life up to 5 yr of age minus the dry periods. Three data files were analyzed: herds with one breed of cows, herds with Holstein and Brown Swiss, and herds with Holstein and Jersey cows. Breed × region interaction was usually significant, with larger effects for the southern regions. Jerseys obtained largest values for the ratio of DIM to days lived, and for the number of completed lactations to 5 yr of age. Brown Swiss had the largest probabilities of surviving to 5 yr of age (stayabilities) in all regions. For the other traits, the results for Brown Swiss were inconsistent, but usually the cows of this breed had shorter herd-life and DIM to 5 yr of age than Holsteins. Brown Swiss cows were expected to have more total DIM in their lifetime in the Southeast than Holsteins. Survival analysis gave the most readily interpretable information, although the linear, poisson, and logistic analyses answered slightly different questions. Adjustment for herd size did not modify the results.     

Genetic evaluation of calving ease for Brown Swiss and Jersey bulls from purebred and crossbred calvings

The objective of this study was to examine the feasibility of implementing routine national calving ease (CE) genetic evaluations of Brown Swiss (BS) and Jersey (JE) sires that include records of crossbred calvings. Records were available for 11,793 BS calvings, 3431 BS-sired crosses, 65,293 JE calvings, and 7090 JE-sired crosses. Evaluations were performed for each breed using only purebred calvings and using both purebred and crossbred calvings. In the latter evaluations, the sire-maternal grandsire model used for the routine evaluation of Holstein (HO) CE was modified to include a fixed breed composition effect to account for differences between purebred and crossbred calvings. Jersey cows had very little calving difficulty (0.5 to 0.7%) and JE bulls had a very small range of evaluations, suggesting that a routine JE evaluation would be of little value. Results from the BS evaluations suggest a routine evaluation would provide BS breeders with a useful tool for genetic improvement. Further examination of data showed that many BS calvings were in mixed herds with HO calvings. As a result, a joint evaluation for BS and HO bulls was developed. The BS data showed that there is similar genetic variability as found in the HO population, which suggests implementation of a routine evaluation including BS CE would be of value. It appears BS bulls may produce daughters with superior maternal calving ability compared with HO. Validation of the joint evaluation was performed by comparing results with the routine HO evaluation. Holstein solutions from the joint evaluation were comparable to results from the routine HO-only evaluation. Correlations among solutions and evaluations showed HO evaluations were not adversely affected by BS data and BS sires were reranked as compared with the BS-only evaluation.     

Reproductive Performance of Crossbred and Purebred Dairy Cows

Analysis of 3095 records from purebred and crossbred dairy cows at five research stations of Agriculture Canada showed that the additive, maternal, and heterosis effects on kind of birth, placental condition, and percent of male or female dead calves were of minor importance.In 3108 records of purebred cows, the number of dead calves did not depend on whether or not the calf was purebred or crossbred or if it was born in first, second, third, or fourth lactation. However, 3080 records from cows of Holstein and Ayrshire lines and crossbred cows resulting from crossing the two lines gave results of higher mortalities of Holstein calves than of Ayrshire or crossbred cows. Holstein cows also had more abnormal births than cows in other genetic groups. Placental condition did not vary among the genetic groups of cows. Rebreeding rate, defined as percentage of cows pregnant for the second time based on the number of heifers calving for the first time, less the number of heifers culled for reasons other than reproduction, was 88% for Holstein and crossbred cows and 78% for Ayrshire cows. Reduction of cows in the herds from first to third lactation was the same for Holstein and crossbred cows (63%) but 77% for Ayrshires. Means of days to first service, number of services per conception, calving interval, and gestation period were almost identical for each genetic group of cows.     

Economic merit of crossbred and purebred US dairy cattle

Heterosis and breed differences were estimated for milk yield traits, somatic cell score (SCS), and productive life (PL), a measure of longevity. Yield trait data were from 10,442 crossbreds and 140,421 purebreds born since 1990 in 572 herds. Productive life data were from 41,131 crossbred cows and 726,344 purebreds born from 1960 through 1991. The model for test-day yields and SCS included effects of herd-year-season, age, lactation stage, regression on sire's predicted transmitting ability, additive breed effects, heterosis, and recombination. The model for PL included herd-year-season, breed effects, and general heterosis. All effects were assumed to be additive, but estimates of heterosis were converted to a percentage of the parent breed average for reporting. Estimates of general heterosis were 3.4% for milk yield, 4.4% for fat yield, and 4.1% for protein yield. A coefficient of general recombination was derived for multiple-breed crosses, but recombination effects were not well estimated and small gains, not losses, were observed for yield traits in later generations. Heterosis for SCS was not significant. Estimated heterosis for PL was 1.2% of mean productive life and remained constant across the range of birth years. Protein yield of Brown Swiss x Holstein crossbreds (0.94 kg/d) equaled protein yield of purebred Holsteins. Fat yields of Jersey x Holstein and Brown Swiss x Holstein crossbreds (1.14 and 1.13 kg/d, respectively) slightly exceeded that of Holsteins (1.12 kg/d). With cheese yield pricing and with all traits considered, profit from these crosses exceeded that of Holsteins for matings at breed bases. For elite matings, Holsteins were favored because the range of evaluations is smaller and genetic progress is slower in breeds other than Holstein, in part because fewer bulls are sampled. A combined national evaluation of data for all breeds and crossbreds may be desirable but would require an extensive programming effort. Animals should receive credit for heterosis when considered as mates for another breed.     

Survival, lifetime production, and profitability of Normande × Holstein, Montbéliarde × Holstein, and Scandinavian Red × Holstein crossbreds versus pure Holsteins

Pure Holstein (HO) cows (n=416) were compared with Normande (NO) × HO (n=251), Montbéliarde (MO) × HO (n=503), and Scandinavian Red (SR) × HO (n=321) crossbred cows for survival, lifetime production, and profitability in 6 commercial herds in California. The SR crossbred cows were sired by both Swedish Red and Norwegian Red bulls. Cows calved from June 2002 to January 2009. For analysis of survival to subsequent calvings, lifetime production, and profitability, data were restricted to 3 of 6 herds because they had at least 20 cows in each of the breed groups. All cows had the opportunity to calve at least 4 times. Best prediction, which is used by USDA for national genetic evaluations in the United States, was used to determine lifetime production to 4 yr (1,461 d) in the herd after first calving from test-day observations. Production and survival were estimated after 4 yr to calculate lifetime profit. A profit function was defined to include revenues and expenses for milk, fat, protein, and other solids production; somatic cell count; reproduction; feed intake; calf value; salvage value; dead cow disposal; and fixed cost. The NO × HO (1.2%), MO × HO (2.0%), and SR × HO cows (1.6%) had significantly fewer deaths than did pure HO cows (5.3%) during the first 305 d of first lactation. All crossbred groups had significantly more cows that calved a second, third, and fourth time, and had mean survival that was 300 to 400 d longer than did pure HO cows. The NO × HO, MO × HO, and SR × HO cows had significantly higher lifetime fat plus protein production than did pure HO cows up to 1,461 d after first calving. For profitability (ignoring possible differences in health costs), NO × HO cows had 26% greater projected lifetime profit per cow, but 6.7% less profit per cow-day, than did pure HO cows. On the other hand, MO × HO and SR × HO cows had 50 to 44%, respectively, more projected lifetime profit per cow and 5.3 to 3.6%, respectively, more projected profit per cow-day than did pure HO cows.     

Differences in body temperature regulation during heat stress and seasonal depression in milk yield between Holstein,Brown Swiss,and crossbred cows

It is not clear whether cattle that are genetically superior in regulation of body temperature during heat stress are also better able to sustain milk production during hot conditions. Objectives were to evaluate differences in body temperature regulation during heat stress between Holstein, Brown Swiss, and crossbred cows under semi-tropical conditions and test whether the seasonal depression in milk yield was greater for genetic groups less able to regulate body temperature. For the first objective, conducted during heat stress, vaginal temperature was measured at 15-min intervals for 5 d in 133 pregnant lactating cows. Vaginal temperatures were affected by time and interaction between genetic group and time. Vaginal temperatures were higher for Holsteins for most times of the day. Moreover, the maximum daily vaginal temperature was higher for Holstein (39.8 ± 0.1°C) than for Brown Swiss (39.3 ± 0.2°C) or crossbreds (39.2 ± 0.1°C). For the second objective, 6,179 lactation records from 2,976 cows were analyzed to determine effects of genetic group and season of calving (cool season = Oct to March; warm season = April to Sept) on 305-d milk yield. Milk yield was affected by genetic group and season but not by the interaction of genetic group and season. The difference in average 305-d milk yield between cows calving in cool versus hot weather was 310 kg (4% decrease) for Holstein, 480 kg (7% decrease) for Brown Swiss, and 420 kg (6% decrease) for crossbreds. In conclusion, Brown Swiss and crossbreds regulated body temperature during heat stress better than Holsteins but these breeds were not more resistant to heat stress with respect to milk yield. Thus, genetic differences in thermotolerance are likely to exist that are independent of regulation of body temperature.     

Multiparity evaluation of calving ease and stillbirth with separate genetic effects by parity

Evaluations that analyze first and later parities as correlated traits were developed separately for calving ease (CE) from over 15 million calving records of Holsteins, Brown Swiss, and Holstein-Brown Swiss crossbreds and for stillbirth (SB) from 7.4 million of the Holstein CE records. Calving ease was measured on a scale of 1 (no difficulty) to 5 (difficult birth); SB status was designated as live or dead within 48 h. Scores for CE and SB were transformed separately for each trait by parity (first or later) and calf sex (male or female) and converted to a unit standard deviation scale. For variance component estimation, Holstein data were selected for the 2,968 bulls with the most records as sire or maternal grandsire (MGS). Six samples were selected by herd; samples ranged in size from 97,756 to 146,138 records. A multiparity sire-MGS model was used to calculate evaluations separately for CE and for SB with first and later parities as correlated traits. Fixed effects were year-season, calf sex, and sire and MGS birth years; random effects were herd-year interaction, sire, and MGS. For later parities, sex effects were separated by parity. The genetic correlation between first and later parities was 0.79 for sire and 0.81 for MGS for CE, and 0.83 for sire and 0.74 for MGS for SB. For national CE evaluations, which also include Brown Swiss, a fixed effect for breed was added to the model. Correlations between solutions on the underlying scale from the January 2008 USDA CE evaluation with those from the multiparity analysis for CE were 0.89 and 0.91 for first- and later-parity sire effects and 0.71 and 0.88 for first- and later-parity MGS effects; the larger value for later parity reflects that later parities comprised 64% of the data. Corresponding correlations for SB were 0.81 and 0.82 for first- and later-parity sire effects and 0.46 and 0.83 for first- and later-parity MGS effects, respectively. Correlations were higher when only bulls with a multiparity reliability of >65% were included. The multiparity analysis accounted for genetic differences in calving performance between first and later parities. Evaluations should become more stable as the portion of a bull's observations from different parities changes over his lifetime. Accuracy of the net merit index can be improved by adjusting weights to use evaluations for separate parities optimally.     

Short communication: Genetic evaluation of stillbirth in US Brown Swiss and Jersey cattle

Stillbirth (SB) often results in reduced milk yield, compromised reproductive performance, and decreased dam longevity. Corrective mating can be used as a short-term solution to the problem, but long-term improvement of the population requires the routine calculation of genetic evaluations. Breeding values for SB have been available for Holstein (HO) bulls since 2006, but not for Brown Swiss (BS) or Jersey (JE) bulls. In this study, a multi-breed sire-maternal grandsire threshold model was used to perform genetic evaluations for SB of BS, JE, and HO bulls using more than 14 million purebred and crossbred calving records. Phenotypically, the percentage of SB (%SB) across all lactations were 3.7% in JE, 5.1% in BS, and 6.3% in HO. Direct heritabilities for BS, JE, and HO were 0.008, 0.007, and 0.008, and maternal heritabilities were 0.002, 0.016, and 0.021, respectively. Compared with HO, crossbred calvings from BS and JE bulls bred to HO cows lowered %SB by 1.5 and 1.2%, respectively. In general, %SB increased considerably as calving difficulty increased in all 3 breeds; however, in JE, %SB was constant for dystocia scores of 3 (needed assistance), 4 (considerable force), and 5 (extreme difficulty). Compared with purebred HO calvings, purebred BS and JE calvings had lower phenotypic %SB by up to 5.5 and 7.8%, respectively, and BS × HO and JE × HO crossbred calvings decreased %SB by up to 3.8 and 4.1%, respectively. As expected, SB rates in primiparous cows were higher than those in multiparous cows. Female calves had greater %SB than male calves in all parities for JE and in second-and-later parities for BS. Favorable (decreasing) phenotypic and genetic trends from 1999 to 2009 were observed in all 3 breeds. Heterosis of SB for BS and JE was −0.026 and −0.149, respectively, on the underlying scale, which corresponds to effects on service-sire SB (SSB) and daughter SB (DSB) predicted transmitting ability (PTA) of −0.3 and −0.5% in BS, and −1.5 and −2.7% in JE. Overall, in the current population, BS bulls had the most desirable average SSB PTA of 4.8%, compared with 5.6% for JE and 5.5% for HO. Brown Swiss and JE bulls both had average DSB PTA of 6.5%, lower than that of 7.7% in HO. Average reliabilities of SSB and DSB in 3 breeds ranged from 45 to 50%. The use of a BS-JE-HO multibreed genetic evaluation for SB in the United States is feasible, and the addition of SSB and DSB to the lifetime net merit selection index will help improve the profitability of BS and JE cattle in the United States.     

Use of sexed semen and its effect on conception rate, calf sex, dystocia, and stillbirth of Holsteins in the United States

Use of sexed semen for artificial insemination of US Holstein heifers (1.3 million breedings) and cows (10.8 million breedings) in Dairy Herd Improvement herds was characterized by breeding year, parity, service number, region, herd size, and herd milk yield. Sexed semen was used for 1.4, 9.5, and 17.8% of all reported breedings for 2006, 2007, and 2008, respectively, for heifers, and for 0.1, 0.2, and 0.4%, respectively, for cows. For 2008 sexed semen breedings, 80.5 and 68.6% of use was for first services of heifers and cows, respectively. For cows, 63.1% of 2008 sexed semen use was for first parity. Mean sexed semen use within herd was the greatest for heifers in the Southwest (36.2%) and for cows in the Mideast (1.3%). Mean sexed semen use increased for heifers but changed little for cows as either herd size or herd mean milk yield increased. Availability of sexed semen was examined for Holstein bulls in active AI service; of 700 bulls born after 1993, 37% had sexed semen marketed by mid August 2009. Active AI bulls with marketed sexed semen were superior to average active AI bulls for evaluations of yield traits, productive life, somatic cell score, daughter pregnancy rate, service-sire calving ease, service-sire stillbirth, final score, sire conception rate, and lifetime net merit. The effect of sexed semen use on conception rate, calf sex, dystocia, and stillbirth also was examined for heifers and cows. Mean conception rate for heifers was 56% for conventional and 39% for sexed semen; corresponding conception rates for cows were 30 and 25%. For single births from sexed semen breedings, around 90% were female. Dystocia and stillbirth were more frequent for heifers (6.0 and 10.4%, respectively, for conventional semen; 4.3 and 11.3%, respectively, for sexed semen) than for cows (2.5 and 3.6%, respectively, for conventional semen; 0.9 and 2.7%, respectively, for sexed semen). Difficult births declined by 28% for heifers and 64% for cows with sexed semen use. Stillbirths were more prevalent for twin births except for sexed semen heifer breedings. Stillbirths of single male calves of heifers were more frequent for breedings with sexed semen (15.6%) than conventional semen (10.8%); a comparable difference was not observed for cows, for which stillbirth frequency of single male calves even decreased (2.6 vs. 3.6%). Overall stillbirth frequency was reduced by sexed semen use for cows but not for heifers.     

Genetic analysis of calving difficulty and stillbirth in Norwegian Red cows

The objectives of this study were to infer genetic parameters for stillbirth (SB) and calving difficulty (CD) and to evaluate phenotypic and genetic change for these traits in the Norwegian Red breed. Stillbirth is recorded as a binary trait and calving difficulty has 3 categories: 1) easy calving, 2) slight problems, and 3) difficult calving. The overall mean frequency of SB in Norwegian Red was 3% at first calving and 1.5% for second and later calvings; mean frequency of the category “difficult calving” was 2 to 3% for heifers and 1% for cows at second and later calvings. Mean stillbirth rate has remained unchanged from 1978 to 2004. The proportion of the category “difficult calving” has not changed over the years, but the “slight problems” category increased from 4 to 7% for heifers and from 2 to 3% for cows. A total of 528,475 first-calving records were analyzed with a Bayesian bivariate sire-maternal grandsire threshold liability model. Posterior means of direct and maternal heritabilities were 0.13 and 0.09 for CD, and 0.07 and 0.08 for SB, respectively. Strong genetic correlations were found between direct SB and direct CD (0.79), and between maternal SB and maternal CD (0.62), whereas all genetic correlations between direct and maternal effects within or between traits were close to zero. These positive correlations are favorable in the sense that selection for one of the traits would result in a favorable selection response for the second trait. No genetic correlations between direct and maternal effects imply that bulls should be evaluated both as sire of the calf (direct) and sire of the cow (maternal). No genetic change for SB was found, and a slight genetic improvement for CD was detected.