Multiparous Research Articles

Associations between lameness and production, feeding and milking attendance of Holstein cows milked with an automatic milking system

A longitudinal study involving 73 primiparous (PP) and 47 multiparous (MP) Holstein cows was conducted over an 8-month period to assess the associations between locomotion score (LCS) and milk production, dry matter intake (DMI), feeding behaviour, and number of visits to an automatic milking system (AMS). Twice weekly, all cows were locomotion scored (scale 1-5) by the same observer. Individual eating behaviour and individual feed consumption at each cow visit to the feed troughs, individual milk production, the time of milking, and the number of milkings for each cow were recorded for the day of locomotion scoring and the day before and after. Dependent variables, such as milk yield, DMI, etc. were modelled using a mixed-effects model with parity, LCS, days in milk (DIM), the exponential of -0.05 DIM, and the interaction between parity and LCS, as fixed effects and random intercepts and random slopes for the linear and the exponential of -0.05DIM effects within cow. LCS did not affect time of attendance at feed troughs, but affected the location that cows occupied in the feed troughs. The time devoted to eating and DMI decreased with increasing LCS. Milk production decreased with LCS>3. The number of daily visits to the AMS also decreased with increasing LCS. The cows with high LCS were fetched more often than the cows with low LCS. Overall, PP cows were more sensitive to the effects of increasing LCS than were MP cows. The decrease in milk production observed with increasing LCS seemed to be affected similarly by the decrease in DMI and by the decrease in number of daily visits to the AMS. A further economic loss generated by lame cows with AMS will be associated with the additional labour needed to fetch them.

Genetic parameters of weaning-to-oestrus interval in pigs using Bayesian analysis

Genetic parameters for weaning-to-oestrus interval (WOI) were estimated on 11,026 sows from pig selection farm Ptuj (Slovenia). Univariate analyses of observations of WOI across parities and two-trait analyses of records of primiparous (PP) and multiparous (MP) sows were performed applying Bayesian approach. WOI was analysed on original scale, transformed using a natural log transformation (lnWOI) and considered as a mixture of normal and exponential distributions (trWOI). Statistical model included genotype, season of service as year-month interaction, and parity as fixed effects, and previous lactation length and number of piglets weaned as covariates. Direct additive genetic effect and permanent environment were considered as random effects. (Co)variance components were estimated by Bayesian analyses. Gibbs chains of length between 130,000 and 180,000 were run. Univariate analysis for sows across parities resulted in heritability estimates of 0.06, 0.07, and 0.07 for WOI, lnWOI and trWOI, respectively. Permanent environment (PE) accounted for 26 % of phenotypic variation for WOI and 19 % for both lnWOI and trWOI. In bivariate analysis, heritability was 0.19 in PP and 0.06 in MP. Genetic correlation for WOI between PP and MP was 0.80. The PE proportion was 0.10 in MP sows. Based on genetic parameters, selection on improved rebreeding performance in pigs is expected to be most efficient considering WOI in primiparous and multiparous sows as different traits. Transformation of WOI increased the genetic parameters only slightly.

Single or multiple reproductive experiences attenuate neurobehavioral stress and fear responses in the female rat

The female brain is a dynamic structure, which expresses its plasticity most readily following reproductive experience (RE). In Experiment 1, we generated nulliparous (NP), primiparous (PP), and multiparous (MP) females (none, one, and two litters, respectively). Two weeks following the weaning of the first/second six-pup litters, the age-matched MP and PP and the non-pup-exposed NP animals were subjected to a 60-min restraint stress paradigm (enclosure in a Plexiglas restraint tube). The brains were removed and processed for c-fos immunoreactivity ( c-fos-IR) in CA3 region of the hippocampus (HI) and in basolateral amygdala (BLA). MP and PP females had very similar numbers of c-fos-IR neurons in both HI and BLA, whereas both were lower than NPs. In a second experiment, the same groups were generated, together with primigravid (PG; first pregnancy) and multigravid (MG; second pregnancy) females, tested in late pregnancy. The animals were exposed to a 30-min trial in an open field and were killed, and the brains were again examined for c-fos-IR. The parous and gravid animals displayed less reactivity to the stress of the open field (i.e., reductions in behavioral measures of anxiety) and significantly less c-fos expression in both CA3 and BLA. The gravid animals displayed significantly less c-fos expression in CA3 and BLA compared to parous females, although neither group differed as a result of a second RE. The data suggest that reproductive (viz., hormonal) and/or maternal (viz., pup exposure) experience may inure a female and her brain to stress, rendering her less susceptible to the behavioral—or other—disruptions that stress sensitivity can produce. Together, these data suggest that the experiences of motherhood (pregnancy, pup exposure, suckling stimulation, etc.) summate to produce reductions in anxiety and stress responsiveness that start before and last long after pup exposure and care. Such reductions may be adaptive in the face of demands placed upon the parous vs. the NP female.

Chewing Activity, Saliva Production, and Ruminal pH of Primiparous and Multiparous Lactating Dairy Cows

Four multiparous (MP) and four primiparous (PP) ruminally cannulated lactating Holstein cows were used in a double 4 × 4 Latin square design to study the chewing behavior, saliva production, and ruminal pH of cows in the first or subsequent lactation. Cows were fed one of four diets; three total mixed rations containing 40, 50, or 60% silage (DM basis), and a separate ingredient diet containing 50% concentrate. Dry matter intake was higher for MP cows than for PP cows (19.2 vs. 17.1 kg/d) but not as a percentage of body weight (2.97±0.06%). Multiparous cows spent more time eating than PP cows (260 vs. 213 min/d, respectively), even after adjustment for dry matter intake (13.8 vs. 12.4 min/kg DM). Multiparous cows also spent more time ruminating per day than PP cows (560 vs. 508 min/d, respectively). Eating salivation rate was not affected by parity, but resting salivation rate was higher for MP cows than for PP. Although MP cows spent more time chewing than PP cows, total daily saliva production was only numerically higher for MP cows because the increase in saliva produced during chewing was accompanied by a decrease in saliva produced during resting. Furthermore, pH profiles tended to be lower for MP cows than for PP cows. Multiparous cows may have a greater risk of incurring acidosis than PP cows because increased salivary secretion associated with increased chewing may not sufficiently compensate the increment of fermentation acids produced in the rumen due to high feed intake.

Fat infiltration in liver and activity of lecithin:cholesterol acyltransferase in serum of dry and lactating dairy cows

To study the relationship between fat infiltration in the liver and the decrease in the activity of serum lecithin:cholesterol acyltransferase (LCAT), blood and liver samples were taken from 14 multiparous (MP) and 16 primiparous (PP) dairy cows four weeks and one week before, and one, four and eight weeks after calving. During the dry period, half the animals received a protein supplement. LCAT activity decreased significantly in all groups before parturition, but returned to the initial level within 1–4 weeks after parturition. There were no differences between the feeding groups, but after calving, the LCAT activity in the MP cows was significantly lower than in thePP cows. Fat infiltration was not detected in the PP cows, and in the MP cows fat infiltration was mild and fell within the physiological range. There was no correlation between liver fat content and the activity of LCAT in serum. These results suggest that shortly before and after parturition, the activity of LCAT in serum is limited by post-transcriptional regulation, possibly by the availability of amino acid for export protein synthesis in the liver.

Effects of chromium supplementation on early lactation performance of Holstein cows

Two experiments were conducted to evaluate the effects of chromium (Cr) supplementation on early lactation performance of Holstein cows. Experiment 1 involved 12 primiparous (PP) and 22 multiparous (MP) cows, while exp. 2 involved 18 PP and 22 MP cows. In each trial, cows were fed total mixed rations (TMR) and assigned to one of two treatments: control or 0.5 mg kg−1 supplemental chelated Cr from week 6 prepartum to week 16 postpartum The cortisol response to synthetic adrenocorticotropin (ACTH) intramuscular (i.m.) and the luteinizing hormone (LH) response to synthetic gonadotropin-releasing hormone (GnRH) i.m. were evaluated as well, during weeks 2 and 6 postpartum in exp. 2 During the first 16 wk of lactation, supplemental Cr tended to increase milk yields in PP cows by 13% (P = 0.06) and increased milk production by 7% (P < 0.05) in exps. 1 and 2, respectively, but had no effect in MP cows. Despite increased milk yield, Cr supplementation had no adverse effect on milk composition, reproductive performance, or health status. Furthermore, Cr supplementation tended to increase the milk lactose content in PP cows. Supplemental Cr reduced serum β-hydroxybutyrate levels and may reduce subclinical ketosis in MP cows. In addition, in overconditioned, aged cows, Cr supplementation may reduce the incidence of certain other metabolic disorders. Peak values and production rates of cortisol in Cr-supplemented cows tended to be greater (P < 0.10) than in control cows at week 6 Basal LH concentrations did not differ between the two treatments for either week However, the Cr-supplemented cows released less (P < 0.05) LH than did control cows at week 6. Results from hormonestimulation tests suggest that the Cr-supplemented cows may have experienced a greater stress with their increased milk production. However the time in postpartum anestrus and the time to conception were similar, suggesting that Cr supplementation may have mitigated the slower return to fertility usually seen in higher producing PP dairy cows. Further study is needed to determine the effects of Cr supplementation on reproductive performance, health status, and metabolic disorders in dairy cows. Key words: Chromium, milk production, luteinizing hormone, cortisol, reproduction, dairy cows

Response of dairy cows to barley grain, tallow or whole sunflower seed as supplemental energy in early lactation

Diets containing barley grain (Bar) or supplemental lipid as tallow (Tal) or whole sunflower seed (Sun) as sources of supplemental energy in early lactation were fed to 12 primiparous (PP) and 18 multiparous (MP) cows for 12 wk starting 14 d postpartum. Diets had similar estimated net energy (lactation) content. MP cows had 9.7 and 7.9% higher milk yield with Tal and Sun, respectively, than with Bar, with no apparent difference in mean intake of dry matter (DM). The cows fed the Tal and Sun diets had lower (P < 0.05) DM intakes at weeks 10, 11 and 12 compared with DM intake at week 1 than the cows fed the Bar diet. The milk yield of PP cows was 13% lower with the Tal diet than the other two diets during weeks 1–7, with no difference between Bar and Sun during the experiment. Fat yield was 36% lower with Tal-fed PP cows than with Sun-fed PP cows and 27% higher with Tal-fed MP cows than with Sun-fed MP cows. Weight gain, as opposed to fat production, was favored with Tal-fed PP cows, while weight gain and fat production were equally favored with Sun-fed PP cows. A high acetate to propionate ratio, the result of a higher acid detergent fiber content obtained by replacing barley grain with lipid plus roughage, was responsible for the lactational response of MP cows to supplemental lipid. Key words: Dairy cow, parity, lipid, barley grain, tallow, sunflower seed