The Interaction of Strain of Holstein-Friesian Cows and Pasture-Based Feed Systems on Milk Yield, Body Weight, and Body Condition Score

Environmental Sensitivity of Milk Production in Extensive Environments: A Comparison of Simmental, Brown Swiss, and Tyrol Grey Using Random Regression Models

A total of 25,160 milk test-day records from 2,516 cows in first lactation of 3 dairy cattle breeds [Simmental (n = 1,900), Brown Swiss (n = 444), and Tyrol Grey (n = 172)] in Kosovo were analyzed using nested repeatability and random regression test-day models with varying (co)variance structures. The different models were compared based on likelihood-based criteria. The best model was a second-order random regression model, with heterogeneous cow variance per breed and heterogeneous residual variance per lactation month and breed, which was used for further analysis. The highest milk production was found in Brown Swiss, followed by Simmental and Tyrol Grey. Substantial breed differences were found for the trajectories of cow and residual variances by month of lactation, with the highest variances found for Brown Swiss, followed by Simmental and Tyrol Grey. High cow and residual variances indicated a high degree of environmental sensitivity on the macro- and microenvironmental levels, respectively. Thus, these results indicate increased environmental sensitivity for breeds with higher genetic potential for milk production. These results support the conclusion that dairy cattle production under the current environmental conditions of Kosovo should be based on a breed with moderate production that is robust to the diet offered (e.g., Tyrol Grey).

The Effect of Early-Lactation Feeding Strategy on the Lactation Performance of Spring-Calving Dairy Cows

The objective of this study was to establish the influence of daily herbage allowance (DHA) and supplementation level offered to spring-calving dairy cows in early lactation on animal performance throughout lactation. Sixty-six Holstein-Friesian dairy cows were randomly assigned to a 6-treatment grazing study. The treatments comprised 3 DHA levels (13, 16, and 19 kg of DM/cow; >4 cm) and 2 concentrate supplementation levels (0 and 4 kg of DM/cow per day). Treatments were imposed from February 21 to May 8 (period 1; P1). During the subsequent 4-wk (period 2; P2), animals were offered a DHA of 20 kg of DM/cow and no concentrate. Subsequently, all animals grazed as a single herd to the end of lactation. Sward quality was homogeneous throughout lactation. A low DHA increased sward utilization (+14%) but reduced milk, solids-corrected milk, protein, and lactose yields compared with a high DHA during P1. Concentrate supplementation significantly increased milk, solids-corrected milk, fat, protein, and lactose yields during P1. The positive effect of concentrate supplementation remained throughout P2. A total concentrate input of 380 kg of DM/cow increased total lactation milk (+432 kg), solids-corrected milk (+416 kg), fat (+18 kg), protein (+15 kg), and lactose (+23 kg) yields. Greater P1 body weights were recorded when a high DHA and concentrate were offered. The P1 treatment had no effect on body condition score throughout lactation. The results indicate that offering a low DHA in early spring does not adversely affect total milk production, body weight, or body condition score, and offering concentrate results in a greater total lactation milk production performance.

Influence of Holstein-Friesian Strain and Feed System on Body Weight and Body Condition Score Lactation Profiles

The objective of the present study was to determine effects of strain of Holstein-Friesian and feed system on body weight (BW) and body condition score (BCS; scale of 1 to 5) lactation profiles in seasonal-calving, grass-based milk production systems. The 3 strains of Holstein-Friesian compared differed in milk production potential and were high-production North American (HP), high-durability North American (HD), and New Zealand (NZ). The 3 feed systems compared were a high grass allowance feed system typical of spring-calving herds in Ireland (MP); an increased stocking rate system (HS); and an increased concentrate supplementation system (HC), each maintained within a separate farmlet. The data comprised 20,611 weekly BW and 7,920 BCS records assessed every 3 wk across 5 yr on 584 lactations. An exponential function was used to model BW and BCS lactation profiles across feed systems. Across feed systems, the NZ strain was significantly lighter (545 kg) but had greater average BCS (3.10 units) compared with the HP (579.3 kg and 2.76 units, respectively) and HD strains (583.2 kg and 2.87 units, respectively). Across feeding systems, the HD and HP strains exhibited a greater loss of BCS in early lactation (0.27 and 0.29 units, respectively) compared with the NZ strain (0.21 units). The HP strain failed to gain BCS over the entire lactation. Concentrate input did not affect the rate of BCS or BW loss in early lactation or BCS at 60 DIM. This study extends previous research outlining the greater suitability of the NZ strain to the low-cost grass-based system of milk production predominantly operated in Ireland.

The effect of strain of Holstein-Friesian dairy cow and pasture-based system on grass intake and milk production

The objective of this study was to investigate the effects of strain of Holstein-Friesian cow, pasture-based feeding system (FS) and their interaction on milk production, dry matter (DM) intake and energy balance over 3 years consecutively. The three strains were: high milk production North American (HP), high fertility and survival (durability) North American (HD) and New Zealand (NZ). The FS were: a high grass allowance (HG FS), a high concentrate (HC FS) and a high stocking rate (HS FS). A separate farmlet existed for each FS and a total of 99, 117 and 117 animals were used in year 1, year 2 and year 3, respectively, divided equally between strains and FS. Individual animal intakes were estimated three times each year at pasture; in May (P1), in July (P2) and October (P3), corresponding on average to day 102, 177 and 240 of lactation, respectively. The HP cows achieved the highest milk yield, the NZ the lowest, while the HD was intermediate; the HP achieved the highest solid corrected milk yield with no difference between the NZ and HD strains. The grass DM intake of the HP strain was highest ( P<0·001) in all feeding systems. There was a significant strain×FS interaction for yield of milk, fat and protein, grass DM and total DM intake. The milk production response to the HC FS in P1 and P2 was significantly greater for both the HP and HD strains than for the NZ strain, while in P3 the response was highest for the HP, lowest for the NZ and intermediate for the HD. The reduction in pasture DM intake per kg of concentrate was greatest for the NZ strain, lowest for the HP and intermediate for the HD strain. The NZ strain also had the highest grass DM intake per kg live weight. The existence of strain×FS interactions for production and DM intake indicate that greater knowledge of both genotype and feeding environment is required to predict animal performance.

Economic Comparison of Divergent Strains of Holstein-Friesian Cows in Various Pasture-Based Production Systems

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

Holstein-Friesian Strain and Feed Effects on Milk Production, Body Weight, and Body Condition Score Profiles in Grazing Dairy Cows

Data from 113 lactations across 76 cows between the years 2002 to 2004 were used to determine the effect of strain of Holstein-Friesian (HF) dairy cow and concentrate supplementation on milk production, body weight (BW), and body condition score (BCS; 1 to 5 scale) lactation profiles. New Zealand (NZ) and North American (NA) HF cows were randomly allocated to 1 of 3 levels of concentrate supplementation [0, 3, or 6 kg of dry matter (DM)/cow per d] on a basal pasture diet. The Wilmink exponential model was fitted within lactation (Y(DIM) = a + b e(-0.05 x DIM) + c x DIM). The median variation explained by the function for milk yield was 86%, between 62 and 69% for milk composition, and 80 and 70% for BW and BCS, respectively. North American cows and cows supplemented with concentrates had greater peak and 270-d milk yield. Concentrate supplementation tended to accelerate the rate of incline to peak milk yield, but persistency of lactation was not affected by either strain of HF or concentrate supplementation. No significant strain by diet interaction was found for parameters reported. New Zealand cows reached nadir BCS 14 d earlier and lost less BW (22 kg) postcalving than NA cows. Concentrate supplementation reduced the postpartum interval to nadir BW and BCS, and incrementally increased nadir BCS. New Zealand cows gained significantly more BCS (i.e., 0.9 x 10(-3) units/d more) postnadir than NA cows, and the rate of BCS replenishment increased linearly with concentrate supplementation from 0.5 x 10(-3) at 0 kg of DM/d to 0.8 x 10(-3) and 1.6 x 10(-3) units/d at 3 and 6 kg of DM/d concentrates, respectively. Although there was no significant strain by diet interaction for parameters reported, there was a tendency for a strain by diet interaction in 270-d BCS, suggesting that the effect of concentrate supplementation on BCS gain was, at least partly, strain dependent.

A herd health approach to dairy cow nutrition and production diseases of the transition cow

This paper presents a practical, on-farm approach for the monitoring and prevention of production disease in dairy cattle. This integrated approach, should be used in an interdisciplinary way by farmers, veterinarians, nutrition advisors and other relevant professionals for the improvement of animal health and welfare and producer profitability. The key areas that form the basis for this approach are body condition score management, negative energy balance, hypocalcaemia, rumen health and trace element status. Monitoring criteria are described for each of these key areas, which when considered collectively, will facilitate the assessment of dairy cow health with regard to clinical and subclinical disease. The criteria, which are informed by published scientific literature, are based on farm management and environmental factors, clinical data, milk production records, dietary analysis, and assessment of blood and liver concentrations of various metabolites or trace elements. The aim is to review the efficacy of production disease control measures currently in place, and if necessary to modify them or formulate new ones.

A New Perspective on Management of Reproduction in Dairy Cows: the Need for Detailed Metabolic Information, an Improved Selection Index and Extended Lactation

For lactating dairy cows, we need management tools, that are "clean, green and ethical", cost-effective and easy to use. Specific tools are needed for artificial insemination (AI) after oestrus detection within a few months of calving, and for managing the complex nutritional requirements of cows between successive calvings. Assessment of energy deficit by measurement of body condition score (BCS) has been useful in the past but we now need more sophisticated ways to measure the relationship between adipose tissue and fertility. For this reason, we have focused our attention on the cells of the adipose tissue, the adipocytes, and the role of the hormone that they produce, leptin. This hormone affects pulsatile LH release and, in dairy cows, it seems to be linked to the first postpartum ovulation. Adipocytes are always sensing energy status and they control leptin secretion dynamically, so blood leptin concentrations can change acutely, even when there is no detectable change in BCS. Leptin secretion seems to be determined by the secretory activity of each adipocyte as well as the total mass of adipocytes in the body of the animal (as measured by BCS). The strong relationship between BCS, leptin concentration and reproductive function in dairy cows suggests that we should reconsider the interval of the recovery from prepartum and postpartum damages, the need for high milk yields at the last lactation causing the dry-off stress and the subsequent troubles. We should also re-assess the current drive to reduce calving interval because milk yields during the early stages of lactation are economically very important but high yields seem to cause several metabolic and reproductive disorders in modern dairy cows. In general, the thinking has been that calving interval must be short because short intervals are more profitable. However, if we remember that main product from dairy cows is milk and that a short calving interval is very difficult without reproductive problems, then a longer calving interval might be more sensible and also more profitable. We have example of an extended calving interval in Japan, Supercows which are very rare cows yielding remarkable high milk. Finally, we probably need to improve dairy cows genetically if we are to achieve the goal of "clean, green and ethical" dairy farming. This paper reviews data relevant to these strategies and we conclude that more basic and applied research will be required if we are to find ways to reach that goal.

Non-lactational traits of importance in dairy cows and applications for emerging biotechnologies

Dairy cattle have traditionally been selected for their ability to produce milk and milk components. The traditional single-minded approach to selection of dairy cattle has now changed and secondary traits are being included in selection indices by decreasing the emphasis on production. Greater emphasis on non-production traits reflects the industry's desire for functional dairy cattle. Six broad categories of non-lactational traits are discussed in this review. They are: type; growth, body size and composition; efficiency of feed utilisation; disease resistance, e.g. udder health as measured by somatic cell score; reproduction; and management. Most of these traits can be found within selection indices worldwide, although relative emphasis varies. The non-lactational traits mentioned above are quantitative, meaning that the phenotype in the whole animal represents the sum of lesser traits that cannot be easily measured. The physiological mechanisms that underlie quantitative traits are extremely complex. Genetic selection can be applied to quantitative traits but it is difficult to link successful genetic selection with the underlying physiological mechanisms. The importance that the bovine genome sequence will play in the future of the genetics of dairy cattle cannot be understated. Completing the bovine genome sequence is the first step towards modernising our approach to the genetics of dairy cattle. Finding genes in the genome is difficult and scanning billions of base pairs of DNA is an imperfect task. The function of most genes is either unknown or incompletely understood. Combining all of the information into a useable format is known as bioinformatics. At the present time, our capacity to generate information is great but our capacity to understand the information is small. The important information resides within subtle changes in gene expression and within the cumulative effect that these have. Traditional methods of genetic selection in dairy cattle will be used for the foreseeable future. Most non-lactational traits are heritable and will be included in selection indices if the traits have value. The long-term prognosis for genome science is good but advances will take time. Genetic selection in the genome era will be different because DNA sequence analysis may replace traditional methods of genetic selection.