Genetic and non-genetic factors associated with milking order in lactating dairy cows

The ability to rapidly identify temporal deviations of an animal from its norm will be important in the management of individual cows in large herds. Furthermore, predictors of genetic merit for especially health traits are useful to augment the accuracy of selection, and thus genetic gain, in breeding programs. The objective of this study was to estimate the repeatability of milking order and to quantify the contribution of differences in additive genetic variation to phenotypic differences (i.e., heritability). The data used in this study included 9813 herd milk recording test-day records with time of milking from 85,532 cows in 1143 herds across an 8-year period. Milking order was available for both morning and evening milking for each cow with, on average, 3.33 milk test-day records (i.e., 6.66 milking events) per lactation, and on average 1.62 lactations per cow. Variance components for milking order were estimated using animal linear mixed models; covariance components between milking order and milk yield, milk composition and somatic cell score (i.e., logarithm₁₀ somatic cell count) were estimated also using animal linear mixed models. The heritability of milking order was 0.20 indicating partial genetic control of milking order. The repeatability of milking order within test-day, within lactation, and across lactations was 0.63, 0.51, and 0.47, respectively. Milking order was positively (P < 0.001), but weakly, phenotypically correlated with milk yield (r = 0.04), and milk fat concentration (r = 0.01) and negatively (P < 0.001), but weakly, correlated with milk protein concentration (r = −0.02) and somatic cell score (r = −0.05). Milking order was positively (P < 0.05), although weakly, genetically correlated with milk yield (r = 0.07) and negatively (P < 0.05), but also weakly, genetically correlated with somatic cell score (r = −0.08). This study is the first to show a contribution of additive genetics to milking order in dairy cattle but the genetic correlation between milking order and somatic cell score was weak.     

Reproductive traits in Nubian dairy goats

For 12 months, ten Nubian doe goats were examined daily for oestrus and blood was obtained twice weekly for serum progesterone (P) analysis. Before the onset of regular ovulatory cycles in the autumn, brief increases in serum P were noted. Ovulation without oestrus was associated with the onset of the breeding season in five of 13 instances. Ovarian activity as assessed by corpus luteum (CL) function began in either September or October and ceased in either January or February in nonpregnant does. CL function was absent postpartum until the beginning of the next breeding season. An instance of male pseudohermaphroditism and mucometra is noted.     

Sexual stimulation of male dairy goats

The objective of the present study was to investigate methods for enhancing the sexual performance of male dairy goats in the context of controlled breeding (“hand-mating”) and semen collection. Nine male goats were individually exposed to a single restrained estrous female who served either as a natural-mating stimulus or as a teaser female for semen collection. Tests were conducted under four conditions: (1) with another male watching in a runway adjacent to the test arena (W); (2) after observing the previously tested male court and copulate with the stimulus female (S); (3) a combination of the aforementioned two treatments (S---W); (4) an unstimulated control treatment (C).In the natural-mating tests, sexual performance was significantly enhanced by each of the forms of stimulation. Differences in sexual performance under the three stimulation treatments were not statistically significant. In the artificial-mating tests, latencies to mount and ejaculate (into the artificial vagina) were significantly shortened by the S and S---W treatments, but not by being watched (W treatment). Again, stimulation treatments did not differ significantly.Sexual stimulation did not affect semen volume or concentration.The improved sexual performance of stimulated male goats may result in a significant sav saving of time and labor to animal breeders involved in hand-mating or semen collection.     

Investigation of major gene for milk yield, milking speed, dry matter intake, and body weight in dairy cattle

The main aim of this study was to determine if there exist any major gene for milk yield (MY), milking speed (MS), dry matter intake (DMI), and body weight (BW) recorded at various stages of lactation in first-lactation dairy cows (2543 observations from 320 cows) kept at the research farm of the Swiss Federal Institute of Technology between April 1994 and April 2004. Data were modelled based a simple repeatability covariance structure and analysed by using Bayesian segregation analyses. Gibbs sampling was used to make statistical inferences on posterior distributions; inferences were based on a single run of the Markov chain for each trait with 500,000 samples, with each 10th sample collected because of the high correlation among the samples. The posterior mean (+/-SD) of major gene variance was 2.61 (+/-2.46) for MY, 0.83 (+/-1.26) for MS, 4.37 (+/-2.34) for DMI, and 2056.43 (+/-665.67) for BW. Highest posterior density regions for 3 of the 4 traits did not include 0 (except MS), which supported the evidence for major gene. With additional tests for agreement with Mendelian transmission probabilities, we could only confirm the existence of a major gene for MY, but not for MS, DMI, and BW. Expected Mendelian transmission probabilities and their model fits were also compared.     

Nonsurgical collection of blastocysts from dairy goats

In two trials, eight attempts were made to collect fertilized ova from dairy goats by nonsurgical methods. In both trials the cervix of each doe was dilated by inserting a Laminaria japonica tent device into the cervical canal prior to flushing. In Trial 1, an attempt was made to collect embryos from four nonsuperovulated does by flushing phosphate-buffered saline (PBS) through a rigid pipette. Little fluid and no embryos were recovered from the does. All four donors were in estrus two days after the procedure. In the second trial, FSH-superovulated does were collected on day 5 following estrus. The donors were anesthetized, and a modified Foley catheter was passed through the cervical canal. In three does, a 24 ga. two-way Foley was stiffened with a size 10 (French) polypropylene catheter which penetrated the Foley, extending 7 cm beyond the tip. Recovery of flushing medium with this device was minimal, and laparotomy of one doe revealed a punctured uterus. Replacement of this device with a different catheter, through which a polypropylene catheter (size 5 Fr.) penetrated only 1 to 2 cm, resulted in satisfactory return of infused PBS, and recovery of two blastocysts and one degenerated ovum from this doe. Use of the same device on a second doe without laparotomy resulted in collection of seven blastocysts and three degenerated ova. Of three observed donors that received Laminaria tents (including one which was not flushed) two were in estrus three days after the procedure, while unused synchronized recipients showed normal cycle lengths. Surgical transfer of two blastocysts from each donor to each of two synchronized recipients resulted in the birth of twin kids from one recipient doe. The study demonstrates the feasibility of embryo collection from dairy goats by nonsurgical means.     

Lysine flux in dry and lactating dairy goats

The objective of this experiment was to test the hypothesis that the physiological state of lactation is accompanied by both an increase in total plasma lysine flux (rate of loss and replacement of lysine) and a net reduction in flux through the plasma lysine pool after accounting for lysine secreted in the milk. Eight lactating French Alpine does were primed and infused for three hours with solutions of alpha15N L-lysine HCl in 0.9% saline through indwelling jugular vein catheters. Enrichment of circulating plasma lysine by continuous intravenous infusion of alpha15N L-lysine was used to estimate whole body lysine flux. This procedure was repeated one month after cessation of milking. Total plasma lysine flux was similar for dry and lactating does (116.6 and 123.0 mmol/d, SEM 16.6 mmol), but 54.2 mmol/d lysine was secreted as milk protein during lactation. Direct measurement of lysine absorption from the lower tract and independent measurement of lysine degradation are needed to provide a more complete portrait of caprine lysine kinetics.     

Effect of service on estrus duration in dairy goats

The objective of this research was to determine the effect of sterile service on estrus duration in multiparous and nulliparous dairy goats. Twenty Nubian goats (10 multiparous and 10 nulliparous) were randomly assigned to of 4 treatment groups (n = 5 animals per group). Group MNS, multiparous without service; Group MS, multiparous with service; Group NNS, nulliparous without service and Group NS, nulliparous with service. Estrus was synchronized by utilization of fluorogestone acetate intravaginal pessaries (40 mg.) over a 12-day period plus 250 IU, i.m. of pregnant mare serum gonadotropin (PMSG) at pessary removal. Estrus was detected with the aid of a vasectomized buck for 5 days after pessary removal for 6-hour intervals (0600, 1200, 1800 and 2400 hours). In the groups that were not serviced the teaser was equipped with an apron and was only allowed to mount. In the serviced groups, the teaser was permitted to mount and service each female on 2 occasions during the first 12 hours of estrus. Estrus initiation for Groups NNS, NS, MNS and MS were (mean +/- SD) 61.5 +/- 29.5, 61.2 +/- 35.4, 63.0 +/- 22.2 and 69.6 +/- 32.5 hours, respectively (P>0.05). Estrus duration for the same groups were (mean +/- SD) 42.0 +/- 12.0, 30.0 +/- 6.0, 42.0 +/- 7.3 and 28.8 +/- 10.7 hours, respectively. These results show that estrus duration was shortened by serving (P<0.01), and that there were no differences between multiparous and nulliparous goats with or without serving (P>0.05). It is concluded that estrus duration in goats is shortened by serving and that no differences in duration exist between multiparous and nulliparous.     

Fate of sodium arsenate in dairy sheep and goats

This study followed the uptake, distribution, and elimination of sodium arsenate administered in a single dose and in multiple doses, respectively, to Iranian dairy sheep and goats. In the single dosing study, the blood concentration data fit an open two-compartment model of the form:C _b (t)=?(A+B)e ^?kat +Ae ^?αt +Be ^?βt Absorption distribution and elimination rate constants were statistically significantly different for the two animal species. In the multiple dosing study, arsenic accumulated in the blood of both animal species, as expressed by a one compartment model of the form:C _t =C _ss (1-e ^?kt ) Arsenic was eliminated rapidly at the termination of dosing, with the blood washout half-life being shorter in sheep than in goats. Urinary excretion was the major elimination route from the body of both species.     

Discriminability and preference among milking machine functions by dairy cows

An attempt was made to assess discomfort to the cow associated with milking machine function. Seven cows were presented with conditional discrimination tasks between alternative stimuli, using operant conditioning procedures. No discrimination between stimuli was evident. When allowed to choose between wide and narrow pulsation ratios, the 7 cows failed to do more than respond randomly. Four of the cows who were given a choice between potentially more or less aversive stimuli, pulsation vs. zero pulsation, showed no clear preference. The data suggest either that cows cannot discriminate within the experimental range of machine functions, i.e. that no measurable preference existed, or, under the experimental methods used, that cows could not learn the conditional discrimination required.     

半胱胺促进空怀奶山羊乳腺发育的试验研究

目的：研究半胱胺对空怀奶山羊乳腺发育的影响。方法：选6只空怀奶山羊进行自身前后对照试验。对照期饲喂基础日粮,试验期饲喂基础日粮加CS。结果：与对照期相比,试验期山羊乳腺组织的DNA含量明显升高,RNA含量明显下降,故RNA／DNA值显著下降。试验期血浆GH和PRL水平分别提高61．6％和31．6％。组织学观察发现,对照期乳腺的腺泡很少发育,几乎看不到乳导管;试验期乳腺有明显导管生长和少量腺泡发育。结论：半胱胺能够在一定程度上促进空怀奶山羊乳腺发育。     

Effect of service number on estrus duration in dairy goats

The object of this research was to study the effect of sterile service number on estrus duration in dairy goats. Twenty-four Nubian goats (20 nulliparous and 4 multiparous) were randomly assigned to 1 of 4 treatment groups (n = 6 animals per group). The following Groups were formed: no service (GS-0); 1 service (GS-1); 2 services (GS-2); 3 services (GS-3). Estrus was synchronized by using fluorogestone acetate intravaginal pessaries (40 mg) over a 12-d period plus 400 IU im pregnant mare serum gonadotropin (PMSG) at pessary removal. Estrus was detected by using a vasectomized buck at 6-h intervals over 5 d after pessary removal (at 0600, 1200, 1800 and 2400 h). In the GS-0 group the teaser was outfitted with an apron and was permitted to mount. In the GS-1, GS-2 and GS-3 groups, the teaser was permitted to mount and service 1, 2 and 3 times, respectively, within the first 12 h after initiation of estrus. The duration of estrus for the 4 groups (GS-0, GS-1, GS-2 and GS-3) was (mean +/- SD) 41.0 +/- 5.9, 24.0 +/- 5.4, 22.0 +/- 4.9 and 22.0 +/- 7.2 h, respectively. These results show differences between the serviced groups and the nonserviced group (P<0.01), but they fail to show differences among the serviced groups (P>0.05). It is concluded that sterile service shortens estrus duration and that service number (1, 2 or 3) does not affect estrus duration.     

Optimising profitability and productivity of pasture-based dairy farms with automatic milking systems

There is a large variability in profitability and productivity between farms operating with automatic milking systems (AMS). The objectives of this study were to identify the physical factors associated with profitability and productivity of pasture-based AMS and quantify how changes in these factors would affect farm productivity. We utilised two different datasets collected between 2015 and 2019 with information from commercial pasture-based AMS farms. One contained annual physical and economic data from 14 AMS farms located in the main Australian dairy regions; the other contained monthly, detailed robot-system performance data from 23 AMS farms located across Australia, Ireland, New Zealand, and Chile. We used linear mixed models to identify the physical factors associated with different profitability (Model 1) and partial productivity measures (Model 2). Additionally, we conducted a Monte Carlo simulation to evaluate how changes in the physical factors would affect productivity. Our results from Model 1 showed that the two main factors associated with profitability in pasture-based AMS were milk harvested/robot (MH; kg milk/robot per day) and total labour on-farm (full-time equivalent). On average, Model 1 explained 69% of the variance in profitability. In turn, Model 2 showed that the main factors associated with MH were cows/robot, milk flow, milking frequency, milking time, and days in milk. Model 2 explained 90% of the variance in MH. The Monte Carlo simulation showed that if pasture-based AMS farms manage to increase the number of cows/robot from 54 (current average) to ～ 70 (the average of the 25% highest performing farms), the probability of achieving high MH, and therefore profitability, would increase from 23% to 63%. This could make AMS more attractive for pasture-based systems and increase the rate of adoption of the technology.     

Effects of milking frequency on lying down and getting up behaviour in dairy cows

The objective of this study was to investigate if cows milked twice per day have more difficulty lying down and getting up and spend less time lying than cows milked three times per day. Seventeen cows of the Swedish Red and White Cattle Breed were studied, seven of which were milked twice daily (2M) and ten were milked three times (3M) daily. They were kept in individual cubicles, that were closed in the rear end with a rope. They had free access to a mixture of silage, hay and concentrate. The individual cows were video-recorded for 24h every fourth week, starting four weeks after calving for four times. The 2M cows stood significantly longer, 128.11min, than the 3M cows, 64.88min, (P<0.01) during the 4h before morning milking. The 2M cows also had a tendency for longer duration of standing rumination (P=0.059) as well as significantly more bouts of standing rumination (P<0.01) during these hours than the 3M cows. The cows in the 3M group spent less time on the getting up movement (P<0.05) during the 4h before morning milking. The distribution of the lying bouts during these 4h differed significantly between the groups, where the 3M cows had fewer lying bouts shorter than 15min and more lying bouts longer than 90min. The results indicate that milking three times a day contributes to increased comfort in high-producing dairy cows.     

Secondary prevention of allergic symptoms in a dairy farmer by use of a milking robot

Background

Allergic sensitization and reactions to guinea pig (Cavia porcellus) have been well documented in laboratory animal handlers, primarily manifesting as rhinitis, conjunctivitis, and asthma. Severe allergic reactions, however, are rare.

Methods

We report two patients with severe allergic reactions following non-occupational exposure to guinea pigs. The first patient, an 11-year-old female, developed ocular, nasal, skin and laryngeal edema symptoms immediately after handling a guinea pig. The second patient, a 24-year-old female, developed symptoms of isolated laryngeal edema after cleaning a guinea pig cage. Percutaneous skin testing, RAST, ELISA and ELISA inhibition testing with guinea pig extract were performed.

Results

Both patients had IgE-mediated allergy to guinea pig confirmed by ELISA and either RAST or skin testing. ELISA inhibition studies confirmed the specificity of the IgE reactivity to guinea pig.

Conclusion

Severe IgE-mediated reactions can occur following non-occupational guinea pig exposure. Physicians should be aware of this possibility.     

The economics of fibre and meat on Norwegian dairy goats

Seasonal variations in the volume of milk in Norwegian goat dairy farming complicate the production of brand goat cheeses. In the specialised goat dairy farming system most kids are culled shortly after birth without utilising the meat. In this paper the farm economics of an alternative system with altered period of kidding (currently from January to March) combined with the production of meat and cashmere fibre, is examined. May kidding combined with raising the kids for 8 or 20 months yielded the most promising economical return. Raising the kids for 1 year is also profitable when kidding takes place in February while December kidding seems to perform best with the present system of culling the kids right after birth. Cashmere fibre production seems to be profitable on Norwegian dairy goat farms and fibre and meat could become an option in countries seeking to improve incomes on dairy goat farms. Compared to the present system the changes would also be favourable from an animal welfare point of view.     

Genetic and phenotypic variability among Salmonella enterica serovar Typhimurium isolates from California dairy cattle and humans

Fifty-six human and 24 adult dairy cattle isolates of Salmonella enterica serovar Typhimurium from a single county in California were compared using ribotyping, insertion sequence typing (IS200), pulsed-field gel electrophoresis, plasmid typing, phage typing, and antimicrobial resistance testing. The majority of the isolates fell into one of two groups which were phage types DT104 and DT193. Combining the information from all typing methods, a total of 45 different "clusters" were defined, with 35 of those including only a single isolate. The library of isolates had a high degree of variability, but antibiotic resistance and plasmid typing each defined single clusters in which human or bovine isolates predominated (chi2, P < 0.05).     

Effects of different stimuli of service on estrus duration in dairy goats

The object of this experiment was to study the effects of different stimuli of service on estrus duration in dairy goats. Twenty Nubian goats were assigned randomly to 4 groups of 5 animals each: service (SER), mechanical stimulation of vagina (MES), accessory gland fluid insemination (AGF), and control (CON), Estrus was synchronized by using medroxyprogesterone acetate intravaginal pessaries (60 mg) over a 12-d period. Estrus was detected using 1 aproned vasectomized buck at 6-hour intervals during 5 d after pessary removal (at 0600, 1200, 1800 and 2400 h). In the SER group the male was permitted to service each female. In the MES group, stimulation was accomplished using a penis-like device maintained in the vagina 15 sec with light pressure on the fornix. In the AGF group, 1.0 ml of accessory gland fluid was deposited into the external cervical os. The CON group was only permitted to be mounted. All treatments were performed only once within the first 12 h of estrus. Estrus duration for the SER, MES, AGF and CON groups was (mean +/- SD) 22.8 +/- 5.0, 27.6 +/- 6.8, 37.2 +/- 2.7 and 42.0 +/- 9.5 h, respectively. The SER group was different from the AGF and CON groups (P<0.01), but not from the MES group (P>0.05). The MES group was different from the AGF (P<0.05) and CON groups (P<0.01). The AGF and CON groups did not differ from each other (P>0.05). It is concluded that service shortened estrus duration due to the mechanical effect of stimulation of the penis-like device against the vaginal fornix.