F. Buckley

Effects of Breed and Feeding System on Milk Production, Body Weight, Body Condition Score, Reproductive Performance, and Postpartum Ovarian Function

The objective of this study was to investigate the potential differences among Holstein-Friesian (HF), Montbéliarde (MB), Normande (NM), Norwegian Red (NRF), Montbéliarde x Holstein-Friesian (MBX), and Normande x Holstein-Friesian (NMX) across 2 seasonal grass-based systems of milk production. The effects of breed and feeding system on milk production, body weight, body condition score, fertility performance, hormone parameters, ovarian function, and survival were determined by using mixed model methodology, generalized linear models, and survival analysis. The 5-yr study comprised up to 749 lactations on 309 cows in one research herd. The HF produced the greatest yield of solids-corrected milk, the MB and NM produced the least yields, and NRF, MBX, and NMX were intermediate. The NRF had the lowest body weight throughout lactation, the NM had the highest, and the other breeds were intermediate. Body condition score was greatest for MB and NM, least for HF, and intermediate for NRF, MBX, and NMX. The HF had a lower submission rate and overall pregnancy rate compared with the NRF. The NRF survived the longest in the herd, the HF survived the shortest, and the NM, MB, MBX, and NMX were intermediate. Breed of dairy cow had no effect on selected milk progesterone parameters from 5 d postpartum until 26 d after first artificial insemination. Breed of dairy cow did not influence insulin and insulin-like growth factor-1 around parturition or at the start of the breeding season. Animals offered a high-concentrate diet had greater milk yield, but they did not have improved reproductive performance. Differences observed between the different breeds in this study are a likely consequence of the past selection criteria for the respective breeds.

A comparison of different dairy cow breeds on a seasonal grass-based system of milk production: 1. Milk production, live weight, body condition score and DM intake

Abstract The objective of this study was to compare the performance of Dutch Holstein-Friesian (HF), upgraded Irish Holstein-Friesian (CL), French Montbeliarde (MB) and French Normande (NR) dairy cow breeds on a spring calving grass-based system of milk production. The HF cows produced the highest ( P P P P P P

The influence of strain of Holstein-Friesian cow and feeding system on greenhouse gas emissions from pastoral dairy farms

The purpose of this study was to model the effect of 3 divergent strains of Holstein-Friesian cows in 3 pasture-based feed systems on greenhouse gas (GHG) emissions. The 3 strains of Holstein-Friesian compared were high-production North American (HP), high-durability North American (HD), and New Zealand (NZ). The 3 feed systems were a high grass allowance system (MP, control); high stocking rate system (HS); and high concentrate supplementation system (HC). The MP system had an overall stocking rate of 2.47 cows/ha and received 325 kg of dry matter concentrate per cow in early lactation. The HS system had a similar concentrate input to the MP system, but had an overall stocking rate of 2.74 cows/ha. The HC system had a similar overall stocking rate to the MP system, but 1,445 kg of dry matter concentrate was offered per cow. A newly developed integrated economic-GHG farm model was used to evaluate the 9 milk production systems. The GHG model estimates on-farm (emissions arising within the farms physical boundaries) and production system (incorporating all emissions associated with the production system up to the point milk leaves the farm gate) GHG emissions. Production system GHG emissions were always greater than on-farm emissions, and the ranking of the 9 systems was usually consistent under both methods. The exception was the NZ strain that achieved their lowest GHG emission per unit of product in the HC system when indirect emissions were excluded, but their lowest emission was in the HS system when indirect emissions were included. Generally, the results showed that as cow strain changed from lower (HD and NZ) to higher genetic potential (HP) for milk production, the GHG emission per kilogram of milk solids increased. This was because of a decline in cow fertility in the HP strain that resulted in a higher number of nonproductive animals, leading to a lower total farm milk solids production and an increase in emissions from nonproductive animals. The GHG emission per hectare increased for all strains moving from MP to HS to HC feed systems and this was associated with increases in herd total feed intake. The most profitable combination was the NZ strain in the HS system and this combination resulted in a 12% reduction in production system GHG emission per hectare compared with the NZ strain in the HC system, which produced the highest emissions. This demonstrates that grass-based systems can achieve high profitability and decreased GHG emissions simultaneously.

A comparison of different dairy cow breeds on a seasonal grass-based system of milk production: 2. Reproduction and survival

Reproduction and survival characteristics of Dutch Holstein-Friesian (HF), upgraded Irish Holstein-Friesian (CL), French Montbeliarde (MB) and French Normande (NR) cows were compared over a 5-year period (137 lactations per breed), in a seasonal grass-based milk production system. The HF had the highest (P<0.05) milk yield at first AI, and the NR had the lowest milk yield; the values for the other two breeds were intermediate. The MB and NR had higher (P<0.05) live weight and body condition scores at first AI than the HF and CL. Similarly, the MB and NR had higher (P<0.05) nadir live weights and nadir condition scores. The HF had greater (P<0.05) reduction in body condition score from calving to first AI than the other three breeds. At the end of the 14 weeks of breeding, significantly (P<0.05) more of the HF cows (26.3%) were not pregnant than the CL cows (16.1%); both of these non-pregnancy levels were higher than the corresponding MB (8.8%) and NR (8.1%) levels. Similarly, the pregnancy rate to first AI of the HF was lower (P<0.05) than the MB and NR. Furthermore, the HF cows had extra number of days from calving to conception than the other three breeds (P<0.05). Dairy cow breed had a significant effect on survival; 20.6, 39.7, 49.2 and 55.8% to day 2500 for the HF, CL, MB and NR, respectively. The results of the present study indicate that the reproductive performance and survival of HF with a large proportion of North American genes are low in a seasonal grass-based milk production system.

A comparison between Holstein-Friesian and Jersey dairy cows and their F1 hybrid on milk fatty acid composition under grazing conditions

The objective of this study was to investigate the effect of 2 breeds, Holstein and Jersey, and their F(1) hybrid (Jersey x Holstein) on milk fatty acid (FA) concentrations under grazing conditions, especially conjugated linoleic acid (CLA) and n-3 polyunsaturated fatty acids because of their importance to human health. Eighty-one cows (27 per breed grouping) were allocated a predominantly perennial ryegrass pasture. Samples were collected over 2 periods (June and July). Breed affected dry matter intake and milk production and composition. Holstein cows had the highest dry matter intake (18.4+/-0.40kg of DM/d) and milk production (21.1+/-0.53kg of DM/d). Holstein and Jersey x Holstein cows had similar 4% fat corrected milk, fat yield, and protein yield; with the exception of fat yield, these were all higher than for Jersey cows. Milk fat concentration was highest for Jersey cows and lowest for Holstein cows, with the hybrid cows intermediate. Total FA and linolenic acid intake (1.09+/-0.023 and 0.58+/-0.012 kg/d, respectively) were highest for Holstein cows. In terms of milk FA, Holstein cows had higher contents of C14:1, cis-9 C18:1 and linoleic acid. In turn, Jersey and Jersey x Holstein cows had higher content of C16:0. Milk concentrations of neither the cis-9,trans-11 isomer of CLA nor its precursor, vaccenic acid, were affected by breed. Nevertheless, large variation between individual animals within breed grouping was observed for CLA and estimated Delta(9)-desaturase activity. There was some evidence for a negative heterotic effect on milk concentration of CLA, with the F(1) hybrid cows having lower concentrations compared with the mid parent average. Plasma FA profile did not accurately reflect differences in milk FA composition. In conclusion, there was little evidence for either breed or beneficial heterotic effects on milk FA content with human health-promoting potential, though significant within-breed, interanimal variation was observed.

Comparative grazing behavior of lactating Holstein-Friesian, Jersey, and Jersey × Holstein-Friesian dairy cows and its association with intake capacity and production efficiency

The objectives of this study were to investigate differences in grazing behavior among Holstein-Friesian (HF), Jersey (JE), and Jersey x Holstein-Friesian (F(1)) cows under an intensive, seasonal, grass-based environment and to determine whether associations exist among grazing behavior, intake capacity, and production efficiency. Data from a total of 108 animals (37 HF, 34 JE, and 37F(1)) were available for analysis. Measurements included milk production, body weight (BW), intake, and grazing behavior. Breed group had a significant effect on all of the production, grass dry matter intake, and efficiency parameters investigated. No differences were observed among the breeds for grazing time, number of grazing bouts, grazing bout duration, and total number of bites. Grazing mastications were higher for the JE cows compared with the HF cows. Grass dry matter intake per bite and rate of intake per minute were higher for the HF cows compared with the JE cows. Large differences between the breeds were apparent when grazing behavior measurements were expressed per unit of BW and per unit of intake. In absolute terms, the HF cows spent more time ruminating and had more mastications during rumination than the JE cows. However, when expressed per unit of BW, ruminating time was greater for the JE cows and they tended to have more ruminating mastications compared with the HF cows. Despite these differences, ruminating time and ruminating mastications per unit of intake were similar for the 2 breeds. For the most part, the F(1) cows tended to be similar to the mid-parent mean, but results showed an increase in biting rate, lower grazing duration per bout, and a tendency to achieve a high intake per bite compared with the average of the parent breeds. The results obtained also indicate that inherent grazing and ruminating differences exist between cows varying in intake capacity and production efficiency. Cows with higher intake capacities have increased grazing time and rate of intake per unit of BW. Increased production efficiency, on the other hand, appears to be aided, in particular by improvements in mastication behavior during grazing.

Body condition score and live-weight effects on milk production in Irish Holstein-Friesian dairy cows

The objective of the present study was to quantify the relationships among body condition score (BCS; scale 1 to 5), live weight (WT) and milk production in Irish Holstein-Friesian spring calving dairy cows. Data were from 66 commercial dairy herds during the years 1999 and 2000. The data consisted of up to 9886 lactations with records for BCS or WT at least once pre-calving, or at calving, nadir or 60 days post-calving. Change in BCS and WT was also calculated between time periods. Mixed models with cow included as a random effect were used to quantify the effect of BCS and WT, as well as change in each trait, on milk yield, milk fat concentration and milk protein concentration. Significant and sometimes curvilinear associations were observed among BCS at calving or nadir and milk production. Total 305-day milk yield was greatest in cows calving at a BCS of 4.25 units. However, cows calving at a BCS of 3.50 units produced only 68 kg less milk than cows calving at a BCS of 4.25 units while cows calving at 3.25 or 3.00 BCS units produced a further 50 and 114 kg less, respectively. Cows that lost more condition in early lactation produced more milk of greater fat and protein concentration, although the trend reversed in cows that lost large amounts of condition post-calving. Milk yield increased with WT although the marginal effect decreased as cows got heavier. Milk fat and protein concentration in early lactation also increased with WT pre-calving, calving and nadir, although WT did not significantly affect average lactation milk fat concentration.

Estimation of genotype×environment interactions, in a grass-based system, for milk yield, body condition score, and body weight using random regression models

Abstract (Co)variance components for milk yield, body condition score (BCS), body weight (BW), BCS change and BW change over different herd-year mean milk yields (HMY) and nutritional environments (concentrate feeding level, grazing severity and silage quality) were estimated using a random regression model. The data analysed included records from 7478 multiparous upgraded Holstein–Friesian dairy cows. There were G×E interactions for BCS across all environments and for BW change across different concentrate levels and silage quality environments. There was a three-fold increase in the genetic standard deviation (S.D.) for BCS change to day 60 of lactation (CS60-5) and a doubling of the genetic S.D. for BCS at day 5 (CS5) as silage quality improved. The genetic variance for CS60-5 increased as concentrate level increased and as grazing severity became tighter. There was significant re-ranking of animals for milk yield, CS5 and CS60-5 over the different HMY environments; genetic correlations fell to −0.60 between extreme HMY environments for CS60-5 and were as low as 0.41 for CS5 across different HMY environments.

Trends in milk production, calving rate and survival of cows in 14 Irish dairy herds as a result of the introgression of Holstein-Friesian genes

Trends in milk production, calving rates, and survival were monitored on a potential 5580 primiparous and multiparous Holstein-Friesian dairy cows across 14 Irish seasonal spring-calving dairy farms between the years 1990 and 2001. Over this period calving rate to first service (CALV1) reduced by 0·96% per year (55 to 44%; P, 0·001), calving rate to first and second service (CALV12) reduced by 0·84% per year (77 to 70%; P, 0·001) and herd average parity number reduced by 0·10 lactation per year (4·3 to 3·5; P,0·001). The proportion of North American Holstein Friesian (NAHF) genes in the cows increased by 5·5% per year (8 to 63%; P,0·001), while pedigree index for milk yield (PIMILK) of the cows increased by 25kg per year ( P,0·001). The predicted difference of the sires of the cows for calving interval and survival increased by 0·5 days ( P,0·001) and reduced by 0·12% ( P,0·001) per year, respectively. A negative association was found between increased phenotypic milk yield, NAHF and PIMILK and reduced calving rates as assessed by CALV1 and CALV12. Increased proportion of NAHF genes exhibited a negative effect on survival ( P,0·001) whereas increased levels of heterosis had a positive impact on survival ( P,0·001). The results of the present study indicate that in seasonal calving herds in Ireland a need for direct selection on traits related to fertility and survival is required to arrest and reverse the declining trends in calving rates and survival.

Characterisation of single nucleotide polymorphisms identified in the bovine lactoferrin gene sequences across a range of dairy cow breeds

The lactoferrin gene sequences of 70 unrelated dairy cows representing six different dairy breeds were investigated for single nucleotide polymorphisms to establish a baseline of polymorphisms that exist within the Irish bovine population. Twenty-nine polymorphisms were identified within a 2.2kb regulatory region. Nineteen novel polymorphisms were identified and some of these were found within transcription factor binding sites, including GATA-1 and SPI transcription factor sites. Forty-seven polymorphisms were identified within exon sequences with unique polymorphisms that were associated with amino acid substitutions. These included a T/A SNP, identified in a Holstein Friesian animal, which resulted in a valine to aspartic acid substitution (Val89Asp) in the mature lactoferrin protein. Other SNPs of interest were associated with amino acid substitutions in the lactoferricin B peptide sequence and an A/G SNP, identified in a Jersey animal, was associated with a tyrosine to cysteine change (Tyr181Cys). The polymorphisms identified in the promoter region may have implications relating to lactoferrin expression levels in cows and those identified in the coding sequence indicate the existence of protein variants in the Irish bovine population. The data presented in this study emphasises the potential for lactoferrin to serve as a candidate gene to select for mastitis resistance with the aim of improving animal health.