Lifetime Milk Production Research Articles

Principal component regression analysis to predict lifetime milk yield of Jaffarabadi buffaloes

The study aims to devise most appropriate prediction model for lifetime milk production of Jaffarabadi Buffalo, based on principal components formulated on initially expressed lactation records as predictors. Lactation milk yield, lactation period and peak milk yield records of first, second and third lactations of animals under study were used of 24 years (1987 to 2010). Principal components (PCs) were derived from data set using principal component regression analysis (PCRA), the principal components were used as predictors for predicting lifetime milk yield (LTMY). Multiple linear regression models were fitted to identify the best fitted model for prediction of lifetime milk yield with the first principal component to all principal component as a predictor. The equation LTMY = 7825.8768+2.8118 (PC1) - 13.7098 (PC2) - 599.0908 (PC3) + 3.0266 (PC4) - 8.8196 (PC5) - 257.9315 (PC6) + 2.6042 (PC7) explained 98.9% variation in the estimated values with adjusted R2= 59.09% variation in the estimated values. The curve estimation analysis showing the appropriateness of first seven principal components as predictor was the most appropriate model for lifetime milk yield. These prediction equations may be helpful in selection at an early stage of Jaffarabadi Buffalo based on early part lactation records.

Thermographic assessment of mastitis progression in sahiwal cattle: Insights into the patterns in the natural course of infection

Mastitis is a global concern in the dairy sector, demanding innovative solutions for effective management for quality lifetime milk production. In this study, infrared thermography (IRT) as a non-invasive technology was integrated into routine farm activities for continuous health monitoring of animals. For 30 days, we systematically monitored the udder health status in 40 Sahiwal cows (160 quarters), employing IRT along with the California Mastitis Test (CMT). We also assessed somatic cell count (SCC), microbial identification, and milk quality parameters of representative samples. The thermal imaging data was analyzed, considering both backward propagation from the 0th day to the −10th day and forward propagation from the 0th day to the +10th day. Our findings revealed that on the 0th day, the mean temperatures of the udder surface skin temperature (USST) and teat skin surface temperature (TSST) exhibited differences (p < 0.05) between the quarters affected by sub-clinical mastitis (SCM) and clinical mastitis (CM) in comparison to the healthy quarters, with the highest degree of difference observed. The observed temperature differences between CM and SCM quarters compared to healthy ranged from 1.8 to 3.62 °C and 0.98 to 3.23 °C for USST, and from 1.68 to 3.16 °C and 0.56 to 2.32 °C for TSST, respectively. Furthermore, our observations indicated that both udder and teat quarters responded differently to mastitis. A temperature rise of 1.37 °C in SCM quarters and 1.75 °C in CM quarters was observed between the −10th and -8th day relative to day 0, with the increase being more pronounced in the morning hours. Also, a notable temperature surge occurred during the -2nd and -1st days relative to the 0th day. The log10SCC values and milk quality parameters significantly differed (p < 0.05) between mastitis-affected and healthy samples. In addition, Staphylococcus spp. was identified as the predominant mastitis-causing pathogen in the bacteriological identification conducted in this study. Therefore, IRT efficiently assesses the initiation point of udder infection in Sahiwal cows, aiding in effective udder health management.

Lifetime milk production of Holstein cattle in the humid tropics compared to Holstein-Gyr and Holstein-Brahman crosses.

Crossbred cattle are commonly used for milk production in the tropics, combining the potential benefits of pure breeds with the heterosis effects of the offspring. However, no comprehensive assessment of lifetime productivity for crossbred versus purebred cattle in low-altitude tropical environments has been carried out. The present study compares the lifetime productivity of purebred Holstein (HO, n = 17,269), Gyr (GY4, n = 435), and Brahman (BR4, n = 622) with crossbreds Gyr × Holstein (GY × HO, n = 5521) and Brahman×Holstein (BR × HO, n = 5429) cows from dairy farms located in low and medium altitude tropical regions in Costa Rica. The production traits of interest were age at first calving (AFC), days open (DO), milk production per lactation (TMP), lactation length (LLEN), age at culling (ACUL), and number of lactations (NLAC). Estimates of heterosis were also calculated. The AFC for GY × HO crosses (33-34 months) was not significantly different (p > .05) from HO (33.8 months). For BR × HO crosses, a significant (p < .05) decrease in AFC (BR3HO1 35.6 months, BR2HO2 34.5 months, and BR1H03 33.3 months) was observed as the fraction of HO breed increased. Estimates of heterosis for AFC were favourable for both crosses, of a magnitude close to 3%. The DO for F1 crosses (GY2HO2 94 days; BR2HO2 96 days) was significantly (p < .05) lower than HO (123 days). Estimates of heterosis for DO were also favourable and above 15% for both crosses. The TMP and LLEN were higher for HO (TMP = 5003 kg; LLEN = 324 days) compared with GY × HO (TMP = 4428 to 4773 kg; LLEN = 298 to 312 days) and BR × HO (TMP = 3950 to 4761 kg; LLEN = 273 to 313 days) crosses. Heterosis for TMP was favourable but low for both crosses, with a magnitude below 3.0%. The NLAC for HO (4.6 lactations) was significantly (p < .05) lower than F1 (GY2HO2, 5.8 lactations; BR2HO2, 5.4 lactations). Heterosis for NLAC was above 6.0% for both crosses. Overall, estimates of lifetime income over feed costs per cow on average were USD 2637 (30.3%) and USD 734 (8.4%) higher in F1 GY × HO and BR × HO, respectively, compared to HO. In conclusion, crossbred animals, specifically those with Gyr and Brahman genetics, extend the productive lifespan, increasing economic returns.

Alternative Traits for Genetic Evaluation of Mastitis Based on Lifetime Merit.

Genetic selection has achieved little progress in reducing mastitis incidence. Mastitis traits are problematic due to the lack of sensitivity of the data and reliance on clinical diagnosis, often missing subclinical cases, and/or on monthly somatic cell count (SCC) measurements. The current measure for mastitis is the lactation average of the somatic cells score (LSCS). We studied two datasets: (1) 148 heifers divided into non-intramammary infected, sub-clinically infected and clinical mastitis groups; (2) data from 89,601 heifers from Israeli Holsteins through the same period divided into "udder healthy" (UH) and "non-healthy" (UNH) by a threshold of SCC 120,000 cells/mL in all nine monthly milk recordings. In study 1, non-infected heifers had significantly (p < 0.05) more partum, production days and overall lifetime milk production compared to clinical and sub-clinically infected. In study 2, UH heifers (20.3%) had significantly higher (p < 0.01) lifetime milk, production days, and lactations. Subdividing datasets by sires, the same analyses detected differences in percentages of UH daughters between the sire groups. Lifetime milk production correlated (r = +0.83, p < 0.001) with udder health status. SCC threshold of less than 120,000 cells/mL during all first lactation measurements indicated healthy udder, providing a valuable insight that this dichotomous trait is advantageous for calculating lifetime net-merit index (NM$) over LSCS.

Effect of non-genetic factors on lifetime milk production and productive life of Murrah buffaloes

Effect of non-genetic factors on lifetime milk production and productive life of Murrah buffaloes

Comparative study between Shami and Holstein cows for longevity and productive lifetime traits under subtropical conditions

This study aimed to compare the longevity and productive lifetime traits between Shami and Hol-stein cows under subtropical conditions, in addition to assess the effect of age at first calving (AFC), first lactation milk yield (FLMY), year and season of first calving on the studied traits in both breeds. The available data included 495 records for Shami and 1129 records for Holstein from birth to disposal date during the period from 1982 to 2014.The studied traits were lifespan (LS), productive life (PL), cow efficiency index (CEI), number of calvings (NC), lifetime milk production (LMP), total lactation periods (TLP), lifetime daily milk production (LDMP), and total dry periods (TDP). The least squares means of LS, PL, CEI and NC were 96.3±1.80 months, 73.2±2.80 months, 64.9±0.008 % and 4.3±0.12 calving for Shami cows in respective order. The corresponding figures for Holstein cows were 66.1±1.81 months, 43.5±2.81 months, 56.4±0.012 % and 3.5±0.19 calving, respectively. The means of LMP, TLP, LDMP and TDP were 7713±563.38 kg, 787±33.43 days, 2.7±0.13 kg and 890±25.55 days for Shami cows and 14406±875.77 kg, 1049±51.96 days, 5.9±0.20 kg and 275±39.72 days for Hol-stein, respectively.The effect of breed was highly significant (P&lt;0.01) on all studied traits. Cows for both breeds with AFC less than 24 months had more PL and NC. Also, cows with the highest average FLMY had the highest LMP, LDMP and TLP. It could be concluded that under the subtropical condi-tions, Shami cows exhibit superiority for longevity traits compared to Holstein ones.

Modeling and forecasting of lifetime milk production in Hariana cattle

The present study was conducted on performance records of 648 Hariana cattle with respect to first lactation and lifetime traits spread over a period of 57 years (1962-2018) from DUVASU farm, Mathura and 23 years (1995– 2017) from State livestock farm Babugarh, Hapur. Lifetime production traits, viz. Lifetime 2 Milk Yield (LT2MY), Lifetime 3 Milk Yield (LT3MY), Lifetime 4 Milk Yield (LT4MY) and Lifetime 5 Milk Yield (LT5MY) were predicted by multiple linear regression analysis. Step-wise regression procedure was used to predict the lifetime milk yield from first lactation traits, viz. age at first calving (AFC), first calving interval (FCI) and first lactation total milk yield (FLTMY). The optimum models were selected with the help of Akaike information criterion (AIC), Bayesian information criterion (BIC), Mallow’s conceptual predictive value and variance inflation factor. The models with lower AIC, BIC and RMSE values and with higher co-efficient of determination were selected as optimum. The optimal models for lifetime production traits, viz. LT2MY, LT3MY, LT4MY and LT5MY with co-efficient of determination were 75.46%, 66.63%, 59.4% and 55.03%, respectively.

The association of herd performance indicators with dairy cow longevity: An empirical study.

The associations between reproductive performance, milk yield and health status with the risk of culling, and thus with a cow's longevity, have been well documented at the individual cow level. Associations at individual cow level may, however, not be valid at herd level due to interrelated herd management aspects and/or policy restrictions. The objective of this study was to explore the association of herd performance indicators with herd-level dairy cow longevity under Dutch production conditions. Longevity was expressed by three different measures, viz. age at culling, lifetime milk production of culled cows and culling rate. The evaluated herd performance indicators included factors on milk production, youngstock rearing, reproduction and health performance as registered on 10 719 Dutch commercial dairy herds during the period 2007-2016. Averaged over herds and the evaluated period, the age of culled milking cows was 2 139 days (5.8 years, SD±298 days), the lifetime milk production of culled cows was 31 238 kg (SD±7,494 kg), and the culling rate was 0.24 (SD±0.08). A mixed linear regression modelling approach was applied to evaluate the association of each of the three longevity measures with the selected herd performance indicators. The results indicated that only four herd performance indictors (herd size, herd expansion, heifer ratio and the proportion of cows with potential subclinical ketosis) shared significant associations with all three longevity variables. Generally, the strength of the associations between each of the evaluated longevity measures and herd performance indicators was only limited. The absence of strong associations between the longevity measures and herd performance indicators reveal that there is potential of extending cattle longevity without affecting the herd performance in terms of milk production, reproduction and health. Moreover, only part of the observed variance in longevity among the herds over time was explained by the herd performance variables, indicating that differences in longevity at herd level may predominantly be determined by other factors, like farmers' attitude and strategic management.

Impact of amino acid 233 in Tax on bovine leukemia virus infection in Japanese Black cattle

Bovine leukemia virus (BLV) is an economically important pathogen that both causes fatal enzootic bovine leukosis (EBL) and reduces lifetime milk production, reproductive efficiency, carcass weight, and longevity in dairy cows. The virus can be divided into two categories based on the amino acid at position 233 in Tax protein, which activates viral transcription and probably plays crucial roles in leukemogenesis. We recently reported that early-onset EBL in Japanese Black (JB) cattle was frequently caused by L233-Tax–carrying virus. This study examined the impact of BLV infection, the proviral load (PVL), and amino acid 233 in Tax on the outcomes of JB cattle. We measured PVL in cattle enrolled between February 2016 and December 2018, determined the Tax type of the isolates, and performed follow-up until March 2022. The results demonstrated that BLV infection increased the risk of involuntary culling and mortality in JB cattle in a PVL-dependent manner. Infection with L233-Tax–carrying virus increased the likelihood of mortality by 1.6-fold compared with the effects of P233-Tax–carrying virus infection. Intrauterine and perinatal infections were frequently caused by L233-Tax–carrying virus, and these infections were likely to influence the early onset of EBL in JB cattle. Conversely, breeding cows infected with P233-Tax–carrying virus were often eliminated by involuntary culling. These findings indicate that amino acid 233 in Tax has importance in terms of preventing economic loss attributable to EBL in JB cattle.

The association of dairy cattle longevity with farm level technical inefficiency.

Prolonging dairy cattle longevity is regarded as one of the options to contribute to a more sustainable milk production. Cattle longevity is a direct result from culling decisions, which is primarily driven by economic considerations. As a consequence, at the herd level, cattle longevity can have effects on the efficiency of dairy production. This study investigates the technical inefficiency of dairy input, and its association with cattle longevity under Dutch commercial dairy production conditions, using a two-stage data envelopment analysis (DEA) approach. First, the technical inefficiency of capital, labor, land, seed & crop protection expenses, veterinary services, livestock purchase & services, feed purchase, miscellanea, livestock units and total input on total farm revenues was computed using DEA. Secondly, a bootstrap truncated regression analysis was applied to identify the association of cattle longevity with the evaluated input-specific and total input scores for technical inefficiency. Data were compiled from performance and accountancy records of 1,037 commercial Dutch dairy herds over the period of 2007 to 2014. In general, Dutch dairy farms displayed a relatively good overall technical efficiency, represented by an average inefficiency score of 0.09. The economic benefit of extending cattle longevity was evidenced by the negative association of cattle longevity with total input inefficiency. Of the evaluated inputs, the utilization of livestock units and feed was most efficient, with inefficiency scores below 0.26. This contrasts with the poor input efficiency of capital and livestock purchase & services with inefficiency scores around 0.52. Although the strength of the evaluated associations was generally low, the regression results illustrated that, except for labor, the age of culled cows was significantly negatively associated (P < 0.05) with each of the input inefficiencies. This contrasts with the significant associations of input inefficiencies with lifetime milk production, which were mostly positive. Since lifetime milk production is driven by length of cattle lifespan in combination with production level of the cows, the reverse direction of the associations with the two longevity indices illustrates that prolonging cattle longevity can improve efficiency performance of a dairy farm as long as the milk yield per cow remains unchanged.

Prediction of Lifetime Milk Yield using Principal Component Analysis in Gir Cattle

The objective of the research was to investigate the relationship among production traits i.e., lactation milk yield, lactation length and lactation peak milk yield of the first three lactations using principal component analysis and formulation of prediction equation to predict lifetime milk production in Gir cattle. Data were from multiparous dairy cows of the University farm. Principal component analysis with correlation matrix was used to find the relationship among lactation milk yield, lactation length and lactation peak milk yield of first three lactation and other fixed effects, including the year of calving, season and parity with random effect of sire. The principal components were fitted to identify the best-fitted model for predicting lifetime milk yield using all principal components as a predictor in different combinations. The first six principal components (first lactation milk yield, lactation length and peak milk yield, second lactation milk yield, lactation length and peak milk yield), explained 98% variation in the estimated values with adjusted R2= 59.85% variation in the estimated values. The curve estimation analysis revealed that the first six principal components as the predictor was the most fitting model for predicting lifetime milk yield. The prediction equation found most fitted will be useful for the selection of Gir cattle at an early stage of lactation.

Genetic analysis of first dry period and lifetime performance in Hariana cattle

The present study was aimed to study lifetime milk production of Hariana cattle in organized farms. The nongenetic factors such as period of calving/birth, season of calving/birth, AFC age group and farms on these traits were studied by least-squares analysis and the means were compared using Duncan's multiple range test. The leastsquares means for first dry period, lifetime 2 milk yield, lifetime 3 milk yield, lifetime 4 milk yield, lifetime 5 milk yield and actual lifetime milk yield were estimated as 198.8±6.1 days, 1802.8±42.3 litres, 2797.0±68.6 litres, 3886.6±100.3 litres, 4984.9±141.9 litres and 4598.3±144.7 litres respectively. Farm, season of calving and period of calving had significant effect on first dry period. Farm and AFC class had significant effect on actual lifetime milk yield. Period of birth had significant effect on lifetime 2 milk yield, lifetime 3 milk yield, lifetime 4 milk yield, lifetime 5 milk yield and actual lifetime milk yield. Season of birth had significant effect on lifetime 3 milk yield, lifetime 4 milk yield and lifetime 5 milk yield. The autumn season born animals had lowest first dry period and highest lifetime 2 milk yield, lifetime 3 milk yield, lifetime 4 milk yield, lifetime 5 milk yield and actual lifetime milk yield.

Extraction and Quantitative Analysis of Goat Milk Oligosaccharides: Composition, Variation, Associations, and 2'-FL Variability.

Human milk oligosaccharides (hMOS) are associated with health benefits for newborns. We studied the composition of goat MOS (gMOS) from colostrum up to the 9th month of lactation to conceive an overview of the structures present and their fate. Potential correlations with factors such as age, parity, and lifetime milk production were examined. An effective method for gMOS extraction and ultra-high-performance liquid chromatography coupled to fluorescence detection (UPLC-FLD) analysis was established, following 2-aminobenzamide gMOS labeling. Considerable biological variability was highlighted among the 12 quantified gMOS and the 9 non-quantified structures in the individual milk samples. Most characteristic, 2′-fucosyllactose was present in 73.7% of the milk samples analyzed, suggesting the possibility of a secretor/non-secretor goat genotype, similar to humans. Contributing factors to the observed biological variability were goat age, parity, lifetime milk production, and the kids’ sex. The results significantly contribute to the current understanding of (variations in) gMOS composition.

THE INFLUENCE OF GENOTYPIC FACTORS ON LONGEVITY AND LIFETIME PRODUCTION OF DAIRY COWS

The influence of genotypic factors (breed, Holstein share heredity, line or related group, sire) on the longevity and lifetime production of dairy cows has been investigated. The study was carried out in a retrospective statistical experiment on the commercial dairy farm “Terezyne”, which located in Kyiv region. The formed matrix of observations in the sta format generally contained information about 5703 cows for 458 variables. Holstein cows were characterized by higher longevity (1489 ± 27.8 days) and higher lifetime milk production (21940 ± 500.9 kg), the lowest longevity and lifetime milk production had cows of Ukrainian Red-and-White dairy breed. Holstein cows compared to animals of Ukrainian Red-and-White dairy breed had in average more lactations (+0.57 ± 0.187) and higher number of total calves (+0.59 ± 0.244). They had an advantage in lifespan by 218 ± 80.1 days, productive lifespan – by 326 ± 82.0 days, total lactation length – by 282 ± 62.2 days. During the lifetime, they produced 4119 ± 1398.4 kg more milk and 549.3 ± 99.62 kg more milk fat and milk protein. Lifetime daily milk yield of Holstein cows was on average 2.6 ± 0.37 kg higher, lifetime daily milk fat and milk protein – 208 ± 26.7 g more compared to animals of the Ukrainian Red-and-White dairy breed. Cows of Ukrainian Black-and-White dairy breed in most traits were intermediate between Holstein and Ukrainian Red-and-White dairy breed. While increasing Holstein share heredity the longevity and lifetime production of cows tended for curvilinear growing. Lifetime of Holstein cows (100%) in the herd was 0.16 ± 0.405 lactations and 325 ± 170.7 days (P &lt; 0.1) longer compared to animals with Holstein share heredity less than 75%. Their lifetime milk production was 8969 ± 2351.6 kg (P &lt; 0.001) higher, lifetime milk fat and milk protein production by 709.9 ± 164.73 kg (P &lt; 0.001) higher, lifetime daily yield by 3.0 ± 0.62 kg (P &lt; 0.001) and 250 ± 43.5 g (P &lt; 0.001), respectively, higher. The cows of Starbuck 352790, Valiant 1650414 and Elevation 1491007 lines and daughter of V. Astronomer 2160438 and H. R. Artist 6284191 sires showed the best longevity and lifetime production. The advantage of cows of the related group of Starbuck 352790 in comparison to animals of other lines in total number of lactations was 0.28–1.29, number of total calves – 0.16–1.20, lifespan – 90–508 days, productive lifespan – 116–603 days, total lactation length – 98–500 days, lifetime milk production – 1402–12161 kg, lifetime milk fat and milk protein production – 115–892 kg. Daughters of bull V. Astronomer 2160438 characterized by 0.96–2.72 more total number of lactations than daughters of other bulls; they had 0.80–2.33 higher average number of total calves. In terms of lifespan, productive lifespan and total lactation length, daughters of this bull were predominated the daughters of other bulls by 392–1037, 297–1143 and 278–971 days, respectively. One-way analysis of variance showed that the greatest influence on longevity and lifetime production of dairy cows had a paternal inheritance, the lowest – breed, it means there is a tendency of increasing the influence of genotypic factors on the researched traits while reducing the level of selection group in the system hierarchy. The strength of breed influence (higher level of intraspecific selection system hierarchy) on the traits of longevity and lifetime production of cows ranged from 1.1 to 12.5%, Holstein share heredity – 3.9 to 19.5%, line or related group – 4.0–19.8% and paternal inheritance – 25.0–47.6%. Greater degree of influence of paternal inheritance is explained both by the lowest (basic) level of intrabreed system hierarchy (the closest level of intragroup kinship) and (partially) by a much higher number of gradations of the organized factor.

Genetic factor in the productive longevity of Brown Swiss cows

The results of studies to identify the genetic characteristics of long-lived cows using marker genes of the EAB locus of blood groups are presented. The research was carried out in farms of the Smolensk region on Brown Swiss cows that had completely finished productive use. The scientific and methodological basis of this work was the generally accepted immunogenetic and statistical methods of research and data processing. As a result of the study of erythrocyte antigenic factors of 1866 animals, the advantage in the duration of productive use from 10 to 18 years of cows carrying genetic material marked with EAB-alleles: B1I1Q, G3O1T1A'2E'3F'2K`(Q`), P1QA'1E'1I`, Y2E'3G'Y'G'', Q, B1G2KY2E'1F'O'G`, G2Y2E`1Q`, I1Y2, I1, BQT1A'1P`, B1G2KA'2B'O' was established. The lowest percentage of long-lived cows (under 6 years) the following EAB-allele carrier were identified: I1Y2Y`, G1O`, I1G'G`, QE'1F'O`, B1O3Y2A'1E'3G'P'Q'Y`, I1O1QA'2, O1, O2E'2G"2, G2E'2, G3O1T1Y2E'3F`2. Lifetime was highly positively correlated with lifetime milk production (r = +0.9).

Researching 100 t cows: An innovative approach to identify intrinsic cows factors associated with a high lifetime milk production

Longevity is an important trait both from an economic and social perspective. Modern dairy cows are criticized for their short productive lifespan: only a minority of animals survives to a fourth lactation, implying that most cows are culled before reaching their maximal potential. In contrast, the population of 100 t cows (HT), reaching the threshold of 100,000 kg lifetime milk yield, is growing rapidly. As these cows combine a long lifespan with high functionality, a better understanding of their intrinsic characteristics might help us to improve the overall lifespan and lifetime production in dairy cows. The aim of the present research was to compare HT with their less-producing herd mates in order to identify intrinsic cow factors associated with longevity and high lifetime production. Therefore, we matched 26,248 HT with 691,597 herd mates, born in the same year in the same herd. Data were provided by Coöperatie rundveeverbetering (CRV) and contained birth dates, calving dates, milk yield and dam information. In addition, scores for conformation traits based on classifications in the first lactation and breeding values (for milk yield, fertility, udder health and claw health) were provided. Multivariable conditional logistic regression models were built to identify factors associated with reaching a lifetime milk yield of 100,000 kg. Results revealed cows born in September and born out of heifers to have the highest odds to become a HT. When cows received a score ≥ 83 (population average 80) for udder and feet & legs conformation, they had higher odds of reaching the 100,000 kg threshold. While a greater body condition and larger rump angle increased the odds of becoming a HT, this was decreased in cows with a large body depth. Finally, breeding values for milk yield, fertility, udder health and claw health were positively associated with the likelihood of reaching a lifetime milk yield of 100,000 kg. In conclusion, to increase lifetime milk yield in dairy herds, farmers should select heifers with high scores for conformation traits like udder and feet & legs and high breeding values for milk yield, fertility and udder health. Furthermore, our data suggest that being born in September out of a heifer potentially contributes to reaching a high lifetime milk yield.

An Empirical Analysis on the Longevity of Dairy Cows in Relation to Economic Herd Performance.

Several studies have stated the various effects of an increased dairy cow longevity on economic herd performance, but empirical studies are lacking. This study aimed to investigate the association between longevity of dairy cows and the economic performance of dairy herds based on longitudinal Dutch accounting data. Herd and farm accounting data (n = 855 herds) over the years 2007–2016 were analyzed. Herd data contained yearly averages on longevity features, herd size and several production variables. Longevity was defined as the age of cows at culling and by lifetime milk production of culled cows. Farm accounting data contained yearly averages on revenues, fixed and variable costs of the herds, by which gross margins were defined. Data was analyzed using generalized linear mixed modeling, with gross margin as dependent variable. The independent variables consisted of average age of culled cows, average lifetime production of culled cows, year, herd size, herd intensity (milk production per ha), herd expansion rate, soil type, milking system, successor availability, total full-time equivalent, heifer ratio (% of heifers per cow) and use of outsourced heifer rearing. Herd was included as a random effect to account for the heterogeneity among herds. Descriptive statistics showed that the average age of culled cows was 5.87 (STD = 0.78) years and the average lifetime milk production of culled cows was 31.87 (STD = 7.56) tons per cow with an average herd size of 89 cows (STD = 38.85). The average age of culled cows was stable over the 10 years (variation between 5.79 AND 5.90 years). The gross margin was on average €24.80/100 kg milk (STD = 4.67), with the lowest value in year 2009 and the highest value in year 2013. Gross margin was not significantly associated with age of culled cows and lifetime milk production of culled cows. Variance in longevity between herds was large (STD = 0.78 years) but herds with a higher longevity did not perform economically better nor worse than herds resulting in lower longevity. This indicates that, within current practice, there is potential for improving longevity in order to meet society's concerns on animal welfare and environmental pollution, without affecting the economic performance of the herd.

Understanding the seasonality of performance resilience to climate volatility in Mediterranean dairy sheep

As future climate challenges become increasingly evident, enhancing performance resilience of farm animals may contribute to mitigation against adverse weather and seasonal variation, and underpin livestock farming sustainability. In the present study, we develop novel seasonal resilience phenotypes reflecting milk production changes to fluctuating weather. We evaluate the impact of calendar season (autumn, winter and spring) on animal performance resilience by analysing 420,534 milk records of 36,908 milking ewes of the Chios breed together with relevant meteorological data from eastern Mediterranean. We reveal substantial seasonal effects on resilience and significant heritable trait variation (h2 = 0.03–0.17). Resilience to cold weather (10 °C) of animals that start producing milk in spring was under different genetic control compared to autumn and winter as exemplified by negative genetic correlations (− 0.09 to − 0.27). Animal resilience to hot weather (25 °C) was partially under the same genetic control with genetic correlations between seasons ranging from 0.43 to 0.86. We report both favourable and antagonistic associations between animal resilience and lifetime milk production, depending on calendar season and the desirable direction of genetic selection. Concluding, we emphasise on seasonal adaptation of animals to climate and the need to incorporate the novel seasonal traits in future selective breeding programmes.

Effect of season and temperature before and after calving on the future milk production of born heifers

Effect of season and temperature before and after calving on the future milk production of born heifers

Influence of country of origin and lineage on the lifetime milk production of Holstein cows

&lt;b&gt;This work investigated the percentage influence of country of origin and lineage on parameters of lifetime milk production in Holstein cows brought as heifers to Ukraine from Western Europe. The animals were kept untethered in new, modern, uninsulated steel cowsheds in a large dairy complex. Data from the Orsek dairy management system were used to evaluate randomly selected cows of different origins with complete lactation for lifetime milk, fat and protein yield. Despite significant differences in milk productivity between animals depending on their country of origin and line, the share of the influence of these factors was fairly small. Two-way analysis of variance showed that the percentage influence of the line on lifetime milk yield was 5,5%, and its influence on the yield of milk fat and protein was 6,3-7,8%. The percentage influence of the country of origin was even smaller, at 0,5–2,6% (with a greater impact on milk yield). The rather small effect of the factors studied could be due to the influence of environmental factors (feeding and living conditions), which should be investigated in further studies. &lt;/b&gt;