Gadegaardpallesen6517

g frequency of TMR, without negative effects on dairy cow performance. However, the use of OA resulted in higher milk yield and mitigated TMR temperature rise regardless of feeding frequency. The effect of external factors such as collective stimulation of intake and stage of lactation on feeding frequency effect must be surveyed in further research.We aimed to verify whether a low number of relevant animal-based indicators was able to discriminate 33 semi-intensive (grazing during the day and confinement during the night with access to an outdoor paddock; S-INT) and 8 intensive farms (permanent confinement with access to an outdoor paddock; INT) located in the Mexican semi-desert. In addition, we implemented the resource-based assessment scheme Animal Needs Index (ANI) with the identified animal-based indicators to compare the overall level of welfare in INT and S-INT. In particular, we used a protocol made up of 2 parts. The first comprised 4 evaluation sheets (locomotion, flooring, environment, management) and resource-based indicators derived from ANI, and the second one comprised a set of validated animal-based measures focusing on physical conditions and clinical signs of disease derived from the Animal Welfare Indicators scheme and reported in 2 additional sheets. The scoring system was also derived from ANI, with partial scores for each sheet to riables were also included in the assessment, as 3 out of 6 sheets of the evaluation scheme (i.e., flooring, environment, and health-physical conditions) were scored higher in the S-INT than in the INT. As a consequence, the total score was also higher for S-INT than for INT. We conclude that the selected set of validated animal-based measures was able to discriminate between farms from different production systems. In particular, higher welfare levels were observed in S-INT farms, where the animals were allowed to spend most of the day on natural pasture, compared with INT farms, where the animals were constantly confined. Nevertheless, a certain degree of improvement should also be promoted in terms of anemia and body condition in S-INT farms.Twinning costs the dairy industry an estimated $96 million each year. Sodium butyrate HDAC inhibitor Twin pregnancy occurrence in high-producing dairy cows is primarily a result of multiple ovulations associated with low circulating concentrations of progesterone due to high milk production. The present retrospective observational study aimed to identify associations between (1) previous parity milk yield and subsequent twin birth prevalence, (2) twin birth with same parity milk production and calving interval (CInt), and (3) twin birth and the subsequent twin calving. The final data set included almost 2.9 million US dairy calving and production records between 2001 and 2020. Variables considered were parity, breed, milk production, CInt, calving month, and year. Logistic and linear regression modeling were used to assess the effects of predictors on outcomes. Herd within state was used as a random effect for all regression models. Twin birth probability increased for cows with increased previous parity milk yield independent of breed or parity. Third and greater parity (3+) compared with second parity (2) and all breeds compared with Jerseys were associated with greater twin probability. Calving between April and September that corresponded to conceiving in July through December was associated with greater twin birth probability. Twin births were associated with decreased milk production following the birth event in Holsteins and parity 2 cows and in the calving months between June and September. Surprisingly, twin births in parity 3+ cows were associated with an increased 305-d milk yield. Cows that had a twin birth were more likely to calve twins in the subsequent parity and had a greater risk of having a CInt between 413 and 600 d. The hazard to subsequent calving after single births was greater compared with twin births. These data can be instrumental in guiding research focus on reducing twinning in lactating dairy cows.Two experiments evaluated the effect of supplementation with a bacterial direct-fed microbial on performance and apparent total-tract nutrient digestion of dairy cows. In experiment 1, 30 multiparous cows (75 ± 32 d in milk) were randomly assigned to 1 of 2 treatments fed for 10 wk. All cows were fed a diet containing 23.8% starch. Treatments were top dressed to rations twice daily and consisted of a combination of Lactobacillus animalis (1 × 109 cfu/d) and Propionibacterium freudenreichii (2 × 109 cfu/d; LAPF) or carrier alone (CON). In experiment 2, 6 ruminally cannulated cows (123 ± 129 d in milk) were randomly assigned to a crossover design with two 6-wk periods. Cows received the same CON or LAPF treatment as in experiment 1. Cows were fed the same 23.8% starch diet as experiment 1 during wk 1 through 5 of each period, and then cows were abruptly switched to a 31.1% starch diet for wk 6. For both experiments, intake and milk yield were measured daily, and milk samples were collected weekly. In experimentd to increase starch digestion compared with CON, but the differences were very small (0.59 vs. 0.78% and 98.74 vs. 98.46%, respectively). Digestion of other nutrients was unaffected. In experiment 2, LAPF increased rumen pH following the abrupt switch to the high-starch diet, but milk yield was lower for LAPF compared with CON (35.7 vs. 33.2 kg/d). Contrary to the decrease in fecal starch with LAPF observed in experiment 1, fecal starch tended to be increased by LAPF following the abrupt ration change in experiment 2 (2.97 vs. 2.15%). Few effects of treatment on rumen and fecal microbial populations were detectable. Under the conditions used in our experiments, addition of the bacterial direct-fed microbials did not have a marked effect on animal performance, ruminal measures, or total-tract nutrient digestion.Milk production systems in several countries show considerable differences between seasons. For example, in the Netherlands, cows are kept inside and fed silage in winter, whereas they are on pasture in summer. The differences between seasons affect milk yield and composition and might influence the genetic background of milk production traits. The objective of this study was to estimate phenotypic and genetic effects of season on milk production traits. For this purpose, 19,286 test-day milk production records of 1,800 first-parity Dutch Holstein-Frisian cows were available, and these cows were genotyped using a 50K SNP panel. Phenotypic effects of season were significant for all milk production traits. Effects of season were large for milk fat yield, fat content, and protein content. Genetic correlations between milk production traits in different seasons showed that genotype by season interaction effects were relatively small for most milk production traits. The genetic background of protein content and lactose content seems to be sensitive to seasonal effects.