Effects of calcium soaps of fatty acids on postpartum reproductive function in beef cows.

Twelve multiparous Simmental cows (584 kg) were used to determine the influence of calcium soaps of fatty acids (CSFA) incorporated in a range supplement on postpartum reproductive characteristics. Cows were assigned randomly to receive a control [C; containing grain sorghum (GS) and soybean meal (SBM)] or CSFA-based (containing Megalac [a source of CSFA], GS, and SBM) supplement. Supplements plus prairie hay were individually fed. Diets were isonitrogenous and met the NEm requirement for heavy-milking beef cows in early lactation. Supplement feeding and daily blood collection began at parturition. Calves were removed permanently from cows at 25 +/- 2 d postpartum. Duration of first postpartum estrous cycles was determined by both visual observations and changes in concentrations of progesterone in serum. Concentrations of LH in serum (15-min intervals for 6 h) were determined 12 h before and 48 and 96 h after calf removal. Concentrations of progesterone and estradiol-17 beta in serum were determined daily. Cows receiving CSFA had higher (P = .06) mean concentrations of LH than those receiving C (1.47 vs 1.12 +/- .13 ng/ml). Concentrations of estradiol-17 beta were lower (P less than .02) and serum progesterone were higher (P less than .02) between d 6 and 8 of the induced cycle in CSFA-fed cows. Plasma cholesterol was greater (P less than .01) in cows fed CSFA although plasma triglyceride concentrations were similar between treatments.(ABSTRACT TRUNCATED AT 250 WORDS)     

日粮多不饱和脂肪酸对猪繁殖性能的影响

本文主要从多不饱和脂肪酸(PUFA)的来源、合成途径、作用机理及使用效果等方面阐述了多不饱和脂肪酸影响猪繁殖性能的研究进展。     

日粮n-3多不饱和脂肪酸对母猪繁殖性能的影响

n-3多不饱和脂肪酸作为一种重要的营养物质,能影响家畜繁殖性能。本文主要从n-3多不饱和脂肪酸作用机理、使用效果等方面阐述n-3多不饱和脂肪酸对母猪繁殖性能的影响。     

Calcium salts of fatty acids with varying fatty acid profiles in diets of feedlot-finished Bos indicus bulls: impacts on intake,digestibility, performance,and carcass and meat characteristics

We hypothesized that the inclusion of calcium salts of fatty acid (CSFA) into the diets and the fatty acid (FA) profile of the supplements would impact performance and meat characteristics of Bos indicus bulls. Hence, the objective was to evaluate the effects of CSFA profiles on intake, body weight (BW), carcass, and meat characteristics of feedlot-finished B indicus bulls. Fifty-three Nellore bulls [initial BW 315 ± 5.9 kg and 20 ± 2 mo] were used. At the beginning, 6 bulls were randomly chosen and slaughtered for determination of their BW composition, and the remaining 47 bulls were evaluated during a 140-d experimental period. The bulls were placed in individual pens, blocked according to initial BW and randomly allocated to 1 of the 3 following treatments: (1) control diet containing sugarcane bagasse, ground corn, citrus pulp, peanut meal, and mineral–vitamin mix (CON), (2) CON with the addition of 3.3% of CSFA from soybean oil (CSO), or (3) CON with the addition of a mixture of 3.3% of CSFA from palm, soybean, and cottonseed oils (CPSCO). Diets were offered ad libitum and formulated to be isonitrogenous. Bulls supplemented with CSFA had a greater (P < 0.01) final BW, dry matter intake, average daily gain (ADG), feed efficiency (FE), and FA intake vs. CON. Among carcass parameters, CSFA-supplemented bulls had greater (P < 0.01) carcass ether extract concentration vs. CON bulls. When the CSFA profile was evaluated (CSO vs. CPSCO), CPSCO bulls had a better (P ≤ 0.03) FE, carcass ADG, and hot carcass weight (HCW) vs. CSO bulls. The FA intakes differed among CSFA treatments, as the total saturated, palmitic, and oleic FA intakes were greater for CPSCO (P < 0.01), whereas lower intakes of total unsaturated and polyunsaturated FA (P < 0.01) were observed for CPSCO vs. CSO. Samples from the Longissimus muscle contained greater palmitoleic (P = 0.01) and reduced linoleic (P = 0.02) FA concentrations in CSFA-supplemented bulls vs. CON bulls. In agreement with the FA intakes, CPSCO-supplemented bulls had a greater (P ≤ 0.05) unsaturated FA concentration vs. CSO in Longissimus muscle. In summary, CSFA supplementation improved the performance of finishing B. indicus bulls vs. CON. Moreover, the inclusion of CSFA from palm, soybean, and cottonseed oil benefited the FE, carcass ADG, and HCW compared with the inclusion of CSFA from soybean oil, demonstrating the potential of specific FA for improving the performance and meat quality of B. indicus bulls.     

Effects of temperament and acclimation to handling on reproductive performance of Bos taurus beef females

Two experiments evaluated the effects of temperament and acclimation to handling on reproductive performance of Bos taurus beef females. In Exp. 1, 433 multiparous, lactating Angus × Hereford cows were sampled for blood and evaluated for temperament before the breeding season. Cow temperament was assessed by chute score and exit velocity. Chute score was assessed on a 5-point scale according to behavioral responses during chute restraining. Exit score was calculated by dividing exit velocity into quintiles and assigning cows with a score from 1 to 5 (1 = slowest, 5 = fastest cows). Temperament score was calculated by averaging chute and exit scores. Cows were classified for temperament type according to temperament score (≤ 3 = adequate, > 3 = aggressive). Plasma cortisol concentrations were greater (P < 0.01) in cows with aggressive vs. adequate temperament. Cows with aggressive temperament had reduced (P ≤ 0.05) pregnancy and calving rate and tended to have reduced (P = 0.09) weaning rate compared with cows with adequate temperament. Hence, kilogram of calf born per cow was reduced (P = 0.05) and kilogram of calf weaned per cow tended to be reduced (P = 0.08) in aggressive cows. In Exp. 2, 88 Angus × Hereford heifers (initial age = 206 ± 2 d) were weighed (d 0 and 10) and evaluated for temperament score (d 10). On d 11, heifers were ranked by these variables and assigned to receive or not (control) an acclimation treatment. Acclimated heifers were processed through a handling facility 3 times weekly for 4 wk (d 11 to 39; Mondays, Wednesdays, and Fridays), whereas control heifers remained undisturbed on pasture. Heifer puberty status, evaluated via plasma progesterone concentrations, was assessed on d 0 and 10, d 40 and 50, 70 and 80, 100 and 110, 130 and 140, 160 and 170, and 190 and 200. Blood samples collected on d 10 and 40 were also analyzed for plasma concentrations of cortisol and haptoglobin. Temperament score was assessed again on d 40 and d 200. Acclimated heifers had reduced (P = 0.01) concentrations of cortisol and haptoglobin on d 40 and reduced (P = 0.02) exit velocity on d 200 compared with control heifers. Puberty was hastened in acclimated heifers compared with control (P = 0.01). Results from this study indicate that B. taurus beef cows with aggressive temperament have impaired reproductive performance compared with cohorts with adequate temperament, whereas acclimation to human handling after weaning hastens reproductive development of replacement heifers.     

Physiological responses of newborn Bos indicus and Bos indicus x Bos taurus calves after exposure to cold

Brahman (n = 9) and 1/2 Simmental x 1/4 Brahman x 1/4 Hereford (n = 11) calves were utilized to determine the influence of exposure to cold on the physiology of the neonate. All calves were removed from their dams within 20 min of birth and prior to suckling. Calves were assigned randomly within breed to either a warm (W; 31 degrees C) or cold (C; 4 degrees C) environmental treatment group. Jugular blood samples were collected via indwelling catheters at 20-min intervals for 180 min. At 100 to 120 min of sampling, all calves were given 1.2 liters of colostrum from their dams via stomach tube. At 120 min, C calves were placed in the W environment. Calf vigor score (CVS) and rectal temperature were determined at each time blood was collected. Serum or plasma was analyzed for glucose (GLU), lactate (LAC), blood urea nitrogen (BUN), hemoglobin (HEM), triglyceride (TRG), triiodothyronine (T3), thyroxine (T4), insulin (INS), cortisol (CORT) and nonesterified fatty acid (NEFA) concentration. Rectal temperature was lower (P less than .01) in C Brahman than in W Brahman and C or W crossbred calves. Crossbred calves had higher (P less than .01) CVS than Brahman calves. Calves in W had lower (P less than .01) GLU than C calves. Brahman calves had higher GLU, LAC, BUN, TRG, T3, T4 and CORT (P less than .05) than crossbred calves. The C Brahman calves had the highest (P less than .05) TRG, CORT, T3 and T4 of all groups. Concentration of NEFA were higher (P less than .01) in C than in W calves.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effects of calcium,phosphorus and zinc supplementation on reproductive performance of crossbred dairy cows in Tanzania

The effects of calcium (Ca), phosphorus (P) and zinc (Zn) supplementation on reproductive performance of grazing dairy cows was studied. Forty-eight cows in their first to third parity were allocated to eight groups of 6 animals each, based on stage of lactation and milk yield. Groups 1 (control), 2 (Ca), 3 (P) and 4 (Zn) received, respectively, no mineral supplement, 10 g Ca, 8 g P and 400 mg Zn. The rest of the groups received a combination of Ca/P, Ca/Zn, P/Zn or Ca/P/Zn. Animals were drenched daily. Ovarian activity was determined by progesterone concentrations in milk. Prepartum body condition score (BCS) measured using scale 1–5 was 2.5–3.5. Reproductive problems were observed in all groups except that supplemented with Ca. Cows supplemented with Ca, P, Ca/P, Ca/Zn and Ca/P/Zn had significantly (p < 0.05) shorter interval (30 days) from calving to resumption of oestrus as compared to control (69 days). Intervals from calving to conception and between calvings did not differ significantly between groups (p > 0.05), but were shorter in Ca-supplemented cows. Furthermore, cows in groups 2 and 3 needed an average of 2 services per conception against 3 for cows in other groups. Hence, supplementation with Ca, P and Zn of deficient dairy cows appears to improve reproductive performance.     

Effects of supplementation of whole corn germ on reproductive performance, calf performance, and leptin concentration in primiparous and mature beef cows

A 2-yr study using primiparous and multiparous, spring-calving, crossbred beef cows was conducted to evaluate the effects of supplemental whole corn germ on reproductive performance, calf performance, and serum leptin concentrations. Each year, cows were blocked by age and BCS and assigned randomly to one of three treatments: PRE (n = 115) cows received 1.14 kg/d (DM basis) of whole corn germ for approximately 45 d before calving; POST (n = 109) cows were fed 1.14 kg/d of whole corn germ for approximately 45 d after calving; and control cows (n = 118) were fed similar energy and protein from dry-rolled corn (1.82 kg of DM/d) for 45 d before and after calving. Additionally, PRE cows were grouped with controls after calving, and POST cows were grouped with control cows before calving, so that corn germ-supplemented cows received the control supplement in the alternate feeding period. Cow BW (538 +/- 13 kg) and BCS (5.4 +/- 0.13) did not differ among treatments at any time during the experiment. Calf birth weight (39 +/- 2 kg), weaning weight (225 +/- 7 kg), and age-adjusted weaning weight (234 +/- 8 kg) did not differ because of dam supplementation regimen. Treatment did not affect the proportion of cows exhibiting ovarian luteal activity before the start of the breeding season (67%) or pregnancy rate (91%). The interval from exposure to bulls until subsequent calving did not differ (P = 0.16) among PRE (298 +/- 2.3 d), POST (303 +/- 2.6 d), and control (304 +/- 2.3 d) cows. Leptin concentrations did not differ among treatments and were 2.15 +/- 0.75, 1.88 +/- 0.76, and 1.91 +/- 0.75 ng/mL for control, POST, and PRE cows, respectively. Age and week relative to calving influenced leptin concentration. Primiparous cows had similar leptin concentrations to 3-yr-old and mature cows for wk -7 and -6 relative to calving, but lower (P < 0.10) concentrations than mature cows for wk -5, and lower (P < 0.05) concentrations than either 3-yr-old or mature cows for wk -4 to +7 relative to calving. Serum leptin was correlated with BCS (P < 0.0001; r = 0.35) at initiation of the feeding period and was correlated with BCS (P = 0.02; r = 0.12) and weight (P < 0.01; r = 0.14) at the completion of the supplement period, but it was not correlated with initial BW or interim BCS. Calving interval was not correlated (P > 0.12) with weekly measures of serum leptin concentration. Supplementing beef cows with whole corn germ had no effect on cow performance, calf performance, or serum leptin concentrations of cows.     

大豆油脂肪酸钙制备工艺优化研究

为寻求制备大豆油脂肪酸钙的优化工艺,在复分解法初步研究基础上,采用三因素二次回归正交旋转组合设计,进行了大豆油脂肪酸钙制备工艺参数优化研究,建立了产品得率(Y)与复分解反应温度(X1)、用水量(X2)、超盐量(X3)之间关系的回归方程,即Y=91.48287+1.13938X1+1.82739X2+1.69316X3-1.77741X12-1.91710X22-1.52456X32+0.84250X1X2。从模型推知,当复分解反应温度为64.57℃、用水量为油重的7.58倍、超盐量为12.78%时,得率得到最大值92.74%。验证结果与模型值相符。     

Dietary pectic oligosaccharide supplementation improves rat reproductive performance via regulating intestinal volatile fatty acids during middle gestation

As a kind of green additive, pectic oligosaccharide (POS) may regulate some physiological functions of animals, such as gut health, antioxidant capacity, immunity and lipid metabolism. This study aimed to identify whether POS administration can improve maternal reproduction, and to determine the possible metabolism. A total of 48 pregnant Wistar rats randomly allotted into 2 groups, and each group was fed a diet supplemented with 0 or 800 mg/kg of POS. Pectic oligosaccharide administration increased rat born number (P < 0.05), did not affect rat embryo number on d 7 of gestation, but increased rat fetus number on d 14 of gestation (P < 0.05). On d 14 of gestation, POS treatment improved Lactobacillus and Bifidobacterium populations and volatile fatty acid concentrations of cecal digesta (P < 0.05), hormone (progesterone and nitric oxide) and cytokine (interleukin 2) concentrations of serum (P < 0.05), and antioxidant capacity of serum (increased total antioxidant capacity and decreased malondialdehyde) and placenta (increased total superoxide dismutase, decreased malondialdehyde) (P < 0.05) in pregnant rats. These results suggest that POS administration improved rat reproduction via decreasing fetus loss in middle gestation. This was due to the increased volatile fatty acid concentrations in rat gut improving hormone and inflammatory-cytokine productions, and antioxidant capacity.     

Induction of ovulation with GnRH and PGF2alpha in lactating Bos taurus x Bos indicus cows

Induction of ovulation for timed artificial insemination (TAI) with the Ovsynch protocol was evaluated in 49 anoestrous and lactating Bos taurus x Bos indicus cows. Palpation per rectum and transrectal ultrasonography were used on Days -30, -20, -10 and 0 (start of treatment) to confirm anoestrus but with the presence of follicles > or = 10 mm, and every other day during treatment to determine ovarian activity. Cows were randomly assigned to: (1) Ovsynch (n = 24; Day 0, 200 microg GnRH; Day 7, 150 microg PGF2alpha; Day 9, 200 microg GnRH + TAI 16 to 20 h later) and (2) control (n = 25; no treatment). Rates of ovulation for the first GnRH injection, detection of a corpus luteum (CL) at PGF2alpha injection, pregnancy and induction of cyclicity were greater (P < 0.05) with Ovsynch. There was no effect of body condition score (P > 0.05). In conclusion, the Ovsynch protocol was not effective in obtaining acceptable pregnancy rate for TAI, but it was effective for induction of cyclicity in anoestrous and lactating Bos taurus x Bos indicus cows under tropical conditions.     

Preweaning efficiency for mature cows of breed crosses from tropically adapted Bos indicus and Bos taurus and unadapted Bos taurus breeds

Production data were collected on mature cows produced by mating Angus and Hereford (pooled AH), Brahman (Bh) and Boran (Br), and Tuli, a tropically adapted Bos taurus, sires by AI or natural service to Angus and Hereford cows. These cows were mated to Charolais bulls for the purpose of this study. Within each sire breed of cow, cows were assigned randomly to one of three feeding rates, 49 or 76 g of DMI/ BW0.75 or ad libitum (10 to 12 cows/feeding rate group), with weekly individual animal feed consumption recorded. Lactation yields were recorded via the weigh-suckle-weigh protocol at approximately 14, 28, 56, 84, 112, 140, 168, and 196 d postpartum for each cow/calf pair. Means for milk yield at peak lactation, total milk yields, calf birth weight, age-adjusted weaning weights, preweaning daily gain, and feed efficiency were estimated. Peak yield (kg/d) for Bh (10.3 +/- 0.36) was greater (P < 0.05) than for Tuli (9.0 +/- 0.31). Total yield (kg, 212 d) for Bh (1802 +/- 68) was greater (P < 0.05) than for Tuli (1532 +/- 59). Birth weight of AH (44 +/- 0.9) was heavier than for Bh and Br (P < 0.05). Preweaning daily calf gain (g/d) and adjusted weaning weight (kg) of Bh (813 +/- 28, 212 +/- 6.1) and Br (766 +/- 24, 202 +/- 5.1) differed (P < 0.05) from AH (589 +/- 24, 169 +/- 5.2) and Tuli (634 +/- 24, 176 +/- 5.3). Efficiency estimates (grams of adjusted weaning weight/kilograms DMI of the cow) for Bh (88 +/- 2.5) and Br (85 +/- 2.1) exceeded (P < 0.05) those for Tuli (74 +/- 2.1) and AH (73 +/- 2.1). Bos indicus breed crosses exhibited greater peak and total yield, lower birth weight, greater daily gain and adjusted weaning weight, and higher feed efficiency than did Bos taurus breed crosses (P < 0.05). Total yield, daily gain, adjusted weaning weight, and feed efficiency were higher (P < 0.05) for cows sired by bulls from tropically adapted breeds, and the peak yield was less (P < 0.10). Tuli exhibited lower total yield and birth weight than did Angus/Hereford (P < 0.05). The efficiency of crossbred Tuli cows did not differ from Angus/Hereford F1 females, but neither equaled the efficiency of crossbred cows produced using Bos indicus breeds.     

Metabolizable energy for maintenance of beef-type Bos taurus and Bos indicus x Bos taurus cows in a dry, temperate climate

Metabolizable energy for maintenance (MEm) was estimated using 123 mature cows of eight diverse breed groups. Cows in each breed group were allotted at random 1) to limit-feeding to approximate maintenance or 2) to ad libitum access to feed. The MEm values were calculated by regression of change in body energy on ME intake. The MEm values for mature Hereford, Red Poll, Hereford x Red Poll, Red Poll x Hereford, Angus x Hereford, Angus x Charolais, Brahman x Hereford, and Brahman x Angus breed types were as follows: 145, 169, 148, 149, 144, 152, 139, and 143 kcal.kg-.75.d-1, respectively. Bos indicus-cross cows ranked lowest for MEm/kg.75. Angus x Hereford cows averaged highest in terms of grams of calf weaned per mature female exposed divided by yearly MEm requirement. Hereford x Red Poll reciprocal crosses on average required 640 kcal less total daily MEm per animal than Hereford and Red Poll straightbreds.     

Evaluation of reproductive traits in Bos taurus and Bos indicus crossbred heifers: effects of postweaning energy manipulation

Reproductive traits were evaluated in Bos taurus and Bos indicus crossbred heifers that were fed different diets during the postweaning period. The study was designed in a 2 x 2 x 2 factorial arrangement of treatments. Angus x Hereford (AH; n = 148) and Brahman x Hereford (BH; n = 148) heifers were sorted after weaning by body weight into light (LW) and heavy (HW) weight blocks. Heifers in each weight block were assigned to diets calculated to reach a target weight of 55% (LE) or 65% (HE) of their projected mature weights by the start of the breeding season. Puberty was determined after a 160-d observation period and characterized by the following criteria: 1) behavioral estrus, 2) presence of a palpable corpus luteum (d 6 to 10; estrus = d 0), and 3) rise in serum progesterone above 1 ng/ml (d 6 to 10). A higher (P = .01) proportion of AH heifers than of BH heifers reached puberty by the breeding season (93% vs 67%). Interactions of breed x weight block and energy level x weight block also contributed to this difference. Weight at puberty was heavier (P = .001) among HE than among LE heifers and greater for heifers in HW than for those in LW blocks (P = .02). Differences in prebreeding weight, body condition, average daily gain, hip height, and pelvic area were influenced selectively by breed, energy level, or weight block. Pregnancy rates were higher (P = .01) among AH than among BH heifers. Incidence and severity of dystocia was influenced by the breed x energy level interaction (P = .01). Brahman x Hereford heifers had less (P = .01) dystocia than AH heifers, HE heifers had less (P less than .02) dystocia than LE heifers, and HE-AH heifers had less (P less than .01) dystocia than LE-AH contemporaries. Subsequent duration of the postpartum interval to estrus was shorter (P = .002) among AH than among BH females. Pregnancy rates at the end of the 2nd yr were higher (P = .02) among LW than among HW females and weights were heavier (P = .001) at weaning among calves weaned from BH dams.     

Modulation of post‐partum reproductive performance in dairy cows through supplementation of long‐ or short‐chain fatty acids during transition period

Thirty‐six cross‐bred cows were used to study the effect of long‐chain (flaxseed) or short‐chain (butyric acid) fatty acid supplementation on metabolic status, ovarian function and reproduction performance during transition period. Control cows received a routine feed of transition diet, while the cows in two treatment groups were supplemented with either 750‐g crushed flaxseed or 250 g butyric acid per cow per day. Ovarian activity was monitored by transrectal ultrasonography on 10th, 20th and 30th days post‐partum. Blood samples were collected by jugular venipuncture into heparinized polystyrene tubes; plasma was prepared and stored under ?20 °C until analysis. Results indicated that cows in flaxseed group were in positive energy balance as indicated by lower NEFA and Beta hydroxy Butyrate and higher glucose concentrations. Uterine involution was completed well within 30 days post‐partum in all the cows in flaxseed fed group compared to 76.9% in butyric acid supplemented and 61.5% in control groups. The size of dominant follicle and corpus luteum was significantly higher (p < 0.05) for flaxseed group compared to control group, which in turn resulted in higher concentrations of plasma progesterone. Cows fed on diets supplemented with flaxseed exhibited post‐partum heat earlier and bred sooner (p < 0.05) than control cows. It has been noticed that supplementation of flaxseed and butyric acid enhanced involution of uterus, early resumption of cyclicity and thereby early breeding. However, in view of the encouraging results obtained for flaxseed supplemented group, its organic nature and easier availability at farmer's gate, we concluded that flaxseed can be safely included in transition diet to modulate reproductive performance of dairy cattle.     

Effect of strategic feed supplementation on productive and reproductive performance in yak cows

A total of 2230 yak cows (5-13 years of age) in two populations with different milking systems were investigated. One population had a system of milking once a day (MOD), and the other population twice a day (MTD). The average milk yield of MOD cows was 0.7 +/- 0.2 kg/day within a milking period of 109 +/- 9 days. This compared with an average of 1.24 +/- 0.3 kg/day in 127 +/- 6 days in MTD yaks (p < 0.01). The cows showed a calving rate of 71% under the MOD system and 51.4% under the MTD system. Three farms with a total of 104 MTD cows between six and 12 years of age were used to provide three different feeding groups. The groups were fed with, or without oat hay or highland barley straw in amounts of 1-1.5 kg/head/day from December to April. The three farms were designated as Farm I, Farm II, and Farm III. Farm I had 41 cows with body weight of 230 +/- 67 kg each for grazing with no supplement (GNS). Farm II had 30 animals with body weight of 216 +/- 28 kg each for grazing + oat hay (GOH). Farm III had 33 animals body weight of 221 +/- 34 kg each for grazing + highland barely straw (GBS). The calving rates of the cows in GOH and GBS were 23 and 19% higher, respectively, than GNS cows (p < 0.01), and the highest rate reached 76.7% in GOH. The live weight loss of the cows in GNS was considerably higher (p < 0.01) than in the two other groups. Ten GOH cows and 12 GNS cows were used to collect milk samples for measuring the progesterone concentration using RIA kits provided by IAEA/FAO: Milk was sampled every five days from calving until 90 days postpartum. In the unsupplemented group, milk progesterone (P4) levels suggested that cows had started cyclic ovarian activity by 40 days postpartum, whereas only 25% had been observed in estrus. In the supplemented group, 80% of cows had started cyclic ovarian activity by the same time and 70% had been seen in estrus. Two types of cyclic activity in terms of progesterone changed were found. With Type I (normal), 50 and 80% of cows from GNS and GOH, respectively, had cyclic changes of P4 in milk at 40 days postpartum. With Type II, the P4 levels in the milk remained 0.89 ng/ml until 90 days postpartum. A total of 46 grazing cows between five and 13 years of age (body weight 214 +/- 68 kg) was used to collect blood samples to measure concentrations of nutrient of metabolites at two weeks pre-calving and at two weeks, two months and four months postcalving, respectively. The concentrations of nutrient metabolites [albumin, globulin, urea, beta-hydroxybutyrate (BHB) and inorganic phosphorus] suggested general underfeeding of energy and protein in the winter/late pregnancy period with some recovery in lactation. Energy constraints appeared again as the summer progressed. No dietary phosphate deficiency was found. BHB and albumin testing on serum yaks could be a useful tool to identify poor nutritional status during the winter and so illustrate the need for supplementation.     

Effect of bypass fat supplementation on productive and reproductive performance in crossbred cows

Objectives of the present study were to evaluate the effects of supplementation of bypass fat on milk production and reproductive performance of crossbred cows. Nineteen multiparous crossbred cows (2–4 lactation) were divided in two groups on the basis of most probable production ability (MPPA). The animals in group 1 (nine cows, MPPA 3,441.32 kg, control group G1) were fed chaffed wheat straw, chopped green maize, and concentrate mixture as per requirements while the animals in group 2 (10 cows, MPPA 3,457.2 kg, treatment group G2) were fed the same ration supplemented with 2.5% bypass fat (on DMI basis). The cows of G2 were supplemented bypass fat 40 days prepartum to 90 days postpartum and carry over effect of supplementation on milk production and reproductive parameters was monitored up to 210 days of lactation. Average birth weights of the calves were 24.94 and 27.95 kg in G1 and G2, respectively. The calving per cent in G1 (88.88%) was lower than that of G2 (100%). The time taken for expulsion of fetal membranes was decreased (P < 0.05) by 5.4 h in G2 compared to G1. Days required for involution of uterus was less (P < 0.05) in G2 (35.40 days) than that of G1 (49.44 days). Less number of cases of retention of fetal membranes (RFM) and metritis were observed in G2 as compared to that of G1. The average milk yield (210 days) in G2 was higher (P < 0.05) than that of G1 (18.65 vs 17.57 kg/day). Similarly, the milk yield during the carry over period (90 days) was higher (P < 0.05) in G2 than that of G1 (14.81 vs 13.79 kg/day). The time required for onset of cyclicity was reduced (P < 0.05) by 6.5 days in G2 as compared to that of G1. The service period and AI per conception were also reduced (P < 0.05) in G2 while bypass fat feeding showed no effect on conception rate (P < 0.80). There were no differences between the two groups in plasma cholesterol, progesterone and insulin concentrations. Hence, it was concluded that bypass fat supplementation at 2.5% of DMI increased the milk production and reduced the time required for involution of uterus and commencement of cyclicity. AI per conception, incidences of metritis and RFM were also reduced on supplementing bypass fat.     

L-carnitine supplementation in culture media improves the pregnancy rate of in vitro produced embryos with sexed semen from Bos taurus indicus cows

Tropical Animal Health and Production - The in vitro embryo production industry in the actual world presents some difficulties related to low embryonic production rates, a problem that could be...