Effects of long-term administration of recombinant bovine somatotropin on the concentration of metabolites in milk in different stages of lactation in crossbred Holstein cattle

Effects of long‐term treatment with recombinant bovine somatotropin (rbST) on concentrations of cellular metabolites in the milk of 87.5% crossbred Holstein cattle were performed. The peak milk yield of rbST‐treated animals was 22% higher (P < 0.05) than that of the control animals in early lactation. The mammary glucose uptake of rbST‐treated animals increased in early lactation, but decreased in mid and late lactation, while plasma glucose concentrations were not affected. Lactose and milk triacylglycerol secretion of rbST‐treated animals significantly increased (P < 0.05) when compared with those of control animals in early lactation. The concentrations of milk glucose of rbST‐treated animals significantly increased in early and mid‐lactation (P < 0.05). The concentrations of milk galactose markedly increased (P < 0.05) whereas the concentrations of milk uridine 5′‐diphosphoglucose (UDP‐glucose) and UDP‐galactose showed no significant changes as lactation advances in both groups. The concentrations of isocitrate, 2‐oxoglutarate and citrate in milk from both groups showed no significant changes throughout experiment. The concentration of glucose‐6‐phosphate (G6P), glucose‐1‐phosphate and cyclic adenosine 3,5′monophosphate in milk from both groups markedly decreased as lactation advances exception in early lactation of rbST‐treated animals, which G6P was not affected. These findings suggest that prolonged rbST treatment exerts its galactopoietic action at least in early lactation through both intramammary and extra‐mammary changes. Increases in the concentrations of glucose and G6P in milk maintained the level of pretreatment in early lactation associated with increases in milk yields during rbST administration, reflect their concentrations in the cytosol or Golgi vesicles of mammary cells, which would be one of the factors regulating intermediary metabolites in the lactose biosynthetic pathway.     

Effects of misty‐fan cooling and supplemental rbST on rumen function and milk production of crossbred Holstein cattle during early,mid and late lactation in a tropical environment

Two groups of five crossbred 87.5% Holstein cattle were housed in normal shade only (NS) as non‐cooled cows and in shaded housing with misty‐fan cooling (MF) as cooled cows. The cows were treated with recombinant bovine somatotropin (rbST) in early, mid and late lactation with three consecutive injections of rbST in every 14 days. Ambient temperatures and the temperature humidity index in the NS barn were significantly higher than those of the MF barn, whereas relative humidity in MF was higher than that of NS barn. The DMI of cooled cows were higher than those of non‐cooled cows, and cooled cows exhibited more response to rbST treatment. Exogenous rbST significantly increased milk yield throughout lactation. The rbST‐treated cows had higher total ruminal fermentation products as volatile fatty acid and ammonia nitrogen than the non‐rbST treated cows and associated changes were greater in cooled animals in all stages of lactation. Exogenous rbST increased the concentrations of milk urea nitrogen in both groups. These results suggest that the changes in ruminal fermentation with greater production of total VFA and NH₃N in response to rbST in crossbred cows whether under misty‐fan cooling or not, is in part through an increase in feed intake, thereby making more substrate available to the mammary gland for milk synthesis.     

Effects of long-term exogenous bovine somatotropin on glucose metabolism and the utilization of glucose by the mammary gland in different stages of lactation of crossbred Holstein cattle

The effects of long-term administration of recombinant bovine somatotropin (rbST) on glucose turnover and the utilization of glucose in the mammary gland using a continuous infusion of [3-³H]glucose and [U-¹⁴C]glucose in lactating crossbred Holstein Friesian(HF) cattle were investigated. Glucose turnover of rbST-treated animals was significantly higher than those of control animals ( P  < 0.05) in mid lactation, while plasma glucose concentrations were not affected. The utilization of glucose of non-mammary tissues of rbST-treated animals significantly increased ( P  < 0.05) as lactation advanced. The glucose taken up by the mammary gland in early lactation increased flux through the lactose synthesis and the pentose cycle pathway with significant increases in NADPH formation for fatty acid synthesis during rbST administration. The utilization of glucose carbon incorporation into milk appeared to increase in milk citrate and milk triacylglycerol but not for milk lactose as lactation advances in rbST-treated animals. The stimulant effect for milk yield by rbST treatment was transiently and significantly increased in early lactation and was decreased in late lactation even though there was a high level of udder blood flow. These findings demonstrate that the regulation of biosynthetic capacity within the mammary gland would be influenced more by local than by systemic factors. The proportion of glucose would be metabolized less for lactose synthesis, but metabolized more via the Embden-Meyerhof pathway and the tricarboxylic acid cycle as lactation advances.     

Comparative study on the regulation of body fluids and mammary circulation at different stages of lactation in crossbred Holstein cattle feeding on different types of roughage

The present study was carried out to evaluate the effect of prolonged feeding of urea‐treated rice straw, compared with feeding of hay, on the regulation of body fluids, milk yield and mammary circulation at early lactation (30 days postpartum), mid‐lactation (120 days postpartum) and late lactation (210 days postpartum) in crossbred Holstein Friesians. Sixteen first lactating crossbred Holstein Friesians (HF), consisting of eight animals of two breed types, 87.5%HF and 50%HF, were selected and each breed was randomly allocated into two groups. Each group, consisting of four animals from the same breed, was fed either 5% urea‐treated rice straw or pangola hay (Digitaria decumbens) as the source of roughage in combination with a similar concentrate throughout the experiments. During the course of lactation there were no significant differences in body weight, heart rate, mean arterial blood pressure, plasma osmolality, plasma volume and blood volume among groups of 87.5%HF animals and 50%HF animals fed either hay or urea‐treated rice straw. Water turnover rate, total body water space and total body water as a percentage of body weight of 50%HF animals were significantly higher than those of 87.5%HF animals fed either hay or urea‐treated rice straw. The packed cell volume was significantly higher in all lactating periods of both groups of 50%HF animals in comparison with 87.5%HF animals. The ratio of DM intake to milk production for 87.5%HF animals fed either hay or urea‐treated rice straw was significantly lower than that of 50%HF animals in early lactation. The udder blood flow and milk secretion of 87.5%HF were significantly higher in early lactation and markedly declined when lactation advanced in comparison with those of 50%HF animals fed either hay or urea‐treated rice straw. The ratio of mammary blood flow to milk yield for all groups was in a similar range during early lactation although it significantly increased in mid‐ and late lactation for both groups of 87.5%HF animals. From these results it can be concluded that both 50%HF and 87.5%HF animals feeding on urea‐treated rice straw as a roughage source do not show any undernutritional effects in comparison with those fed with hay during the course of lactation. The physiological response differences between breeds are that 87.5%HF animals, which have a genetic makeup closer to the exotic bos taurus breed and a high milk yield, show a poor adjustment to the tropical environment and poorer lactation persistency in comparison with 50%HF animals.     

Effects of supplemental recombinant bovine somatotropin and mist-fan cooling on the renal tubular handling of sodium in different stages of lactation in crossbred Holstein cattle

The effect of supplementary administration of recombinant bovine somatotrophin (rbST) on the renal tubular handling of sodium in crossbred 87.5% Holstein cattle housed in normal shade (NS) or mist-fan cooled (MF) barns was evaluated. The cows were injected with 500 mg rbST at three different stages of lactation. The MF barn housed cows showed a slightly decreased ambient temperature and temperature humidity index, but an increased relative humidity. Rectal temperature and respiration rates were significantly lower in cooled cows. The rbST treated cows, housed in NS or MF barns, showed markedly increased milk yields, total body water, extracellular fluid and plasma volume levels, along with a reduced rate of urine flow and urinary excretion of sodium, potassium and chloride ions and osmolar clearance, in all three stages of lactation. Renal tubular sodium and water reabsorption were increased after rbST administration without any alteration in the renal hemodynamics. Lithium clearance data suggested that the site of response is in the proximal nephron segment, which may be mediated via increases in the plasma levels of aldosterone and IGF-1, but not vasopressin, during rbST administration.     

Longitudinal observation on reproductive and lactation performances of smallholder crossbred dairy cattle in Fitche,Oromia region,central Ethiopia

A two-year longitudinal study was conducted to assess the reproductive and lactation performances of smallholder crossbred dairy cattle in Fitche, central Ethiopia. Twenty-four smallholder dairy farms were monitored and data on reproductive, breeding, lactation and management aspects of crossbred dairy cows (n = 69) were collected and analysed. Moreover, milk samples were collected and analysed for progesterone. The overall Least-squares means for calving interval (CI), calving to conception interval (CCI) and first observed oestrus after calving were 516, 253 and 141 days, respectively. Suckling significantly prolonged these intervals. The mean first onset of luteal activity (OLA) after calving was 52 days, while 67.4% (n = 43) had a delayed (>55 days) return to cyclicity after calving. Suckling and parity number significantly (p < 0.05) influenced the OLA. The mean lactation length was 54.4 weeks. The overall daily mean milk yield for the first 43 weeks of lactation after calving was 11.7 L/day. The estimated daily milk yield increased slowly and reached peak (13.8 L/day) around the 11th week post partum and declined gradually and steadily. Suckling status, season of calving and parity number significantly influenced the estimated daily milk yield. In conclusion, the present study indicated that the smallholder crossbred dairy cows in the study area had prolonged intervals to first oestrus after calving, to conception and to the next calving, and thus their reproductive performance is unsatisfactory. Delayed first onset of luteal activity (postpartum anoestrus) contributed to these extended intervals. Further detailed investigation is suggested to examine the effects of other relevant factors on the reproductive and lactation performances of smallholder crossbred dairy cows for appropriate intervention.     

Improved milk production through PG–PL system by provision of in‐house shelter management in lactating Murrah buffaloes during winter season

Comprehensive information on the role of β‐casein and plasminogen–plasmin (PG–PL) system in milk secretion of Murrah buffaloes during winter season is lacking, although effects of cold stress can be ameliorated to an extent by altering microclimate at farm level. Hence, this study was aimed to determine the changes in productivity along with PG–PL system of milk, plasma hormones and metabolites of buffaloes during winter (December–January) season under two different management systems. Average minimum temperature and wind chill index during this season were 7.02 and 12.74 °C respectively. Buffaloes were divided in two groups of six animals each: control and treatment, where treatment group animals were placed in‐house with floor bedding of paddy straw and the control group animals in loose housing system without straw bedding. Physiological responses were recorded, and milk and blood samples were collected at weekly intervals for six‐week experimental period. Under in‐house management system, buffaloes experienced better comfort by alleviating environmental stress as their physiological responses such as respiration rate and pulse rate were significantly reduced (p < 0.01) as compared to the control, which subsequently resulted higher milk yield by 9.92% (p < 0.05). Analysis of milk samples revealed higher concentration of plasminogen (10.6 vs. 8.05 μg/ml; p < 0.01) and β‐casein (p < 0.05), and lower plasmin level (0.299 vs. 0.321 μg/ml; p < 0.05) in buffaloes under treatment group. It was also found that plasma cortisol, glucose and non‐esterified fatty acids levels were higher (p < 0.01) in control group as compared to the treatment animals by 13.6%, 8.14% and 12.6% respectively. However, milk composition, growth hormone, epinephrine and norepinephrine level in plasma were similar in both the groups. Hence, it may be concluded that provision of in‐house shelter management with floor bedding of paddy straw during winter was effective to minimize environmental stress and improved milk production through manipulation of PG–PL system in buffaloes.     

Milk yield and reproductive performance of dairy cattle under smallholder management system in North-eastern Amhara Region,Ethiopia

This study was conducted in South Wollo Zone of Amhara Regional State, Ethiopia, to assess the milk yield and reproductive performance of indigenous and crossbred cattle under smallholder management conditions. Questionnaire survey was used to collect retrospective data on the performance of dairy cattle in 186 households. Thirty two postpartum cows (16 indigenous and 16 crossbred) were selected purposively and monitored for five months and milk samples were collected twice per week from each cow to determine postpartum ovarian activity using ELISA techniques. Daily milk yields at all stages of lactation were significantly (P < 0.01) higher in crossbred than indigenous cows. Crossbred cows had significantly (P < 0.01) longer lactation length and shorter age at first calving, while calving interval was significantly shorter in cows that gave previous calves during the wet season than the dry season. Only six cows (18.8%) showed heat signs on an average of 136 days postpartum of which one was a crossbred and five were indigenous. While, 11 cows (34.3%) resumed ovarian activity until 150^th day postpartum among which three were crossbred and eight were indigenous.     

A comparison of the effects of parenteral and oral administration of supplementary vitamin E on plasma vitamin E concentrations in dairy cows at different stages of lactation

As a result of research conducted in the US, recommendations for dry cow vitamin E intakes have increased seven fold there, however there has been no change to recommendations in the UK. As part of a larger study comparing the impact of existing UK and new US recommended vitamin E intakes on the health and fertility of commercial dairy cows in the UK, a study was set up to investigate the effect of route of supplementation and stage of lactation, over a 21 day period, on the response to mega-supplementation of cattle receiving supposedly adequate vitamin E. The study assessed the response of dry, peak lactation and mid lactation cows to in-feed or parenteral vitamin E supplementation (7 animals per treatment/lactation stage group) by measuring plasma and milk vitamin E concentrations, blood glutathione peroxidase (GSH-Px) activity and milk yields over a 21 day period. Plasma vitamin E concentrations were significantly influenced by a time, stage and treatment interaction (P = 0.046). Both dry and lactating animals had significantly higher plasma vitamin E concentrations at some time points in the parenteral supplemented cows compared to the in-feed supplementated animals (P ≤ 0.011 and P < 0.01, respectively). Milk vitamin E concentrations did not significantly differ between lactation stages but treatment had a significant effect on concentrations (P < 0.008) when lactation stage was removed from the model. There was no significant difference in milk yield between treatment groups. A significant relationship between plasma and milk vitamin E concentrations was only found in the parenterally supplemented cows (r = 0.435, P < 0.001). In cattle with intakes greater than the ARC recommendations, measurement of plasma vitamin E concentration may be of limited value in determining whether there has been a response to supplementation. The relationship between plasma and milk vitamin E concentrations is too poor for milk vitamin E concentrations to be used as a proxy for plasma vitamin E.     

Comparison of fattening performance in Brahman grade cattle (Bos indicus) and crossbred water buffalo (Bubalus bubalis) fed on high roughage diet

The objective of this study was to compare the fattening performance in Brahman grade cattle (crossbred cattle) and crossbred water buffalo at the same young age and fed with high roughage based fattening rations in the Philippines. Ten crossbred cattle and 10 crossbred water buffalo, aged between 18 and 24 months old were used in this experiment. The animals were fed diets consisting of 85% Napier or Para grass and 15% concentrate mixture (CM) on a dry matter (DM) basis. The grass, total DM intake and bodyweight gain were significantly (P < 0.01) higher for the crossbred water buffalo than for the cattle. There was no species significant difference in the digestion coefficient and feed conversion rate between the crossbred cattle and water buffalo. The return over feed cost for fattening was significantly (P < 0.05) higher in the crossbred water buffalo than in the cattle. These results clearly indicate that under high roughage‐based fattening rations, young crossbred water buffalo are better able to utilize the roughage and they perform better in terms of feed intake and live weight gains than the crossbred cattle in the Philippines.     

Effect of a treatment with eprinomectin or trichlorfon on the yield and quality of milk produced by multiparous dairy cows

The effects of a strategic antiparasitic treatment against Hypoderma species and other parasites on the milk yield, composition, and somatic cell counts of 742 multiparous dairy cattle were investigated on 79 farms in a Hypoderma species-endemic area in western Switzerland; 357 of the cows were treated with eprinomectin, 252 with trichlorfon, and 133 were left untreated. The treatments were given between October and early December 1998, on average 53 days before calving. Milk yield, fat, protein and somatic cell counts were measured once a month until the end of lactation. Eprinomectin and trichlorfon significantly increased milk yield during the first month after treatment compared with the control cows by 2.14 (P < 0.001) and 2.50 kg per day (P < 0.001), respectively. Initially, the difference between the eprinomectin- and trichlorfon-treated animals was not significant, but the effect of eprinomectin on milk yield was persistent, whereas the effect of trichlorfon decreased significantly by 0.12 kg per day per month (P < 0.05). The somatic cell counts increased significantly slower in the treated cows than in the control cows (P < 0.05). Milk composition was not affected by the treatments.     

The influence of recombinant bovine somatotropin on dietary energy level-related growth of Holstein-Friesian bull calves

Our objective for this study was to assess the effect of recombinant bovine somatotropin (rbST) in overcoming the biological effects attributed to live weight increase and age on growth and fat deposition in male cattle. Holstein-Friesian bull calves (n = 56; 182.2 +/- 14.7 d old) were allotted to four subtreatments in a randomized complete block with a factorial arrangement of two levels of rbST: 0 and 500 mg of Posilac, every 2 wk, and two dietary metabolizable energy (ME) concentrations: low metabolizable energy (LME) and high metabolizable energy (HME); 10 vs 11.3 MJ/kg DM, respectively. The effect of rbST treatment on daily gain was expressed mostly on the HME diets. The rbST treatment had no effect on the animals fed the LME diets before the age of 240 d was reached. Dry matter intake and the effect of rbST treatment on DM intake were inversely related to the energy concentration of the diet. The degree of fatness of the animals was significantly reduced by rbST treatment and significantly increased by energy concentration of the diet. The major effect of rbST, under the experimental conditions, in regards to adipose tissue deposition, was on the fat depots and not on the intramuscular fat. The concentration of bST, IGF-I, and insulin in the plasma was increased (P < .001) owing to rbST treatment. Lower metabolizable energy supply led to a higher (P < .001) plasma bST concentration, nonsignificantly lower plasma IGF-I and thyroid hormone concentrations, and lower (P < .001) plasma insulin concentration. A trend (P = .065) toward an increase in PUFA was found in the muscle of the rbST-treated and the HME diet animals. At a young age, when the natural growth potential is high, rbST treatment will be efficient only when a diet allowing a high digestible energy intake is provided.     

Comparison of carcass and meat characteristics of Brahman grade cattle (Bos indicus) and crossbred water buffalo (Bubalus bubalis) fed on high roughage diet

The objective of this study was to compare the carcass and meat quality in crossbred cattle and crossbred water buffalo at the same younger age and fed with high roughage in the Philippines. Ten crossbred cattle and 10 crossbred water buffalo, with an average age of 22 months (18–24 months) were used in this experiment. The animals were fed a similar diet, which consisted of 85% Napier or Para grass and 15% concentrate mixture on a dry matter basis, for 180 days before slaughter. Slaughter weight of the crossbred water buffalo was higher (P < 0.05) than that of the cattle, although the dressing percentage was significantly (P < 0.01) lower for the former than for the latter. The estimated lean yield was higher (P < 0.05) in crossbred cattle than crossbred water buffalo. The muscle fiber diameter of loin in buffalo meat was smaller (P < 0.05) than that in cattle. In regard to carcass and meat quality, the crossbred water buffalo was comparable or slightly superior to the crossbred cattle in tenderness, sensory score of color (P < 0.01) and flavor (P < 0.05). These results clearly indicate that at a younger age and even under high roughage‐based fattening rations, crossbred water buffalo are able to produce good quality meat, which will be by no means inferior to that of crossbred cattle in the Philippines.     

Effect of ginseng polysaccharides on the immunity and growth of piglets by dietary supplementation during late pregnancy and lactating sows

There are many reports that dietary supplementation with plant polysaccharides in pigs might promote their growth, but little is known about the maternal effect of ginseng polysaccharides (GPS) on piglets’ growth by dietary supplementation to pregnant and lactating sows. In the current study, the effects of dietary supplementation with GPS on the immunity of sows and growth of their piglets were investigated. Results showed no significant difference among the four groups in the total number of piglets, live piglets, weak piglets and birth weight of piglets, indicating the GPS‐treatment has no adverse effect on reproduction. Furthermore, the weaning weight of the GPS‐treated groups was higher than that of control group (P < 0.05); among them, the addition of 200 mg/kg dose has the best effect. Interestingly, GPS increased the total immunoglobulin G concentration in milk and serum of sows (P < 0.05). The concentrations of interleukin (IL)‐2, IL‐6, tumor necrosis factor (TNF)‐α, and interferon‐γ in milk and serum of sows were also increased in the experimental groups relative to the control (P < 0.05). Meanwhile, maternal supplementation of GPS significantly increased IL‐2 and TNF‐α concentration in the piglets’ serum of the experimental groups relative to control (P < 0.05). GPS (200 mg/kg) significantly increased the glutathione peroxidase activity in milk and serum (P < 0.05), while the concentrations of malondialdehyde were significantly reduced (P < 0.05). The present results indicated that GPS supplementation during late pregnancy and lactation improved immunity‐related bio‐molecular levels in sow serum and milk, which may be further beneficial to piglet health and growth through biological transmission effects.     

Effects of stocking density on oxidative stress status and mammary gland permeability in early lactating dairy cows

The current study was conducted to investigate the effect of stocking density (SD) on oxidative stress status and mammary gland permeability in early lactating dairy cows. Thirty‐two dairy cows were allocated into 16 blocks, basing on parity, previous milk yield, and body weight, and were then randomly assigned into one of the two treatments as follows: 75% (75SD) and 100% (100SD) SD. The cows were fed with same diet throughout the 8‐week experimental period. The milk yield and milk sample were collected on two consecutive days during the 8‐week experimental period weekly. Plasma samples were collected on fourth and eighth experimental weeks. Raw, energy‐corrected, and 4% fat‐corrected milk yield were significantly higher in 75SD‐cows than that of 100SD‐animals, respectively. The milk somatic cell count was lower in 75SD‐cows than that of 100SD‐animals. The levels of Na⁺, Na⁺/K⁺, bovine serum albumin and plasmin were lower in 75SD‐cows than those of 100SD‐cattle, respectively. The 75SD‐cows had reduced insulin and insulin/glucagon levels but higher prolactin and growth hormone concentrations, compared with those of 100SD‐animals, respectively. In conclusion, compared with low SD‐animals, early lactating cows with higher SD had higher oxidative stress status, which further led to a greater mammary gland permeability.     

德系西门塔尔杂交母牛头胎泌乳性能测定报告

[目的]为了掌握德系西门塔牛导入张掖牛的产奶情况。[方法]采用级进杂交模式,开展选种选配和群体选育,通过对西弗F1头胎产奶母牛产奶量的测定。通过试验,[结果]表明,西门塔尔杂交牛305d产奶量比对照组提高了600kg以上。[结论]引进德系西门塔尔开展杂交改良达到提高了我市西杂牛泌乳性能的目标,适合在我市引进开展杂交改良,提高母牛的产乳性。     

Milk production increase following treatment of Dutch dairy cattle with thiabendazole

Summary

In a trial involving 542 dairy cattle on 28 farms, 276 were treated once with thiabendazole within two days of calving. The treated group showed an average increase in milk yielded over the non‐return group of 229.8 kg during the subsequent lactation.

In the treated group, total milk fat production was increased over that of the controls by 7.4 kg per cow; milk protein was increased by 6.9 kg per cow. All treatment parameter differences were highly significant at the 1% level of probability.     

Fit of Wood's function to daily milk records and estimation of environmental and additive and non-additive genetic effects on lactation curve and lactation parameters of crossbred dual purpose cattle

The objectives of this study were to estimate the environmental and additive and non-additive genetic effects on lactation curve and lactation parameters of crosses of Holstein (H), Brahman (B) and Brown Swiss (BS) in Olancho region in Honduras. The data consisted of 54,517 milk yield records from 192 dual-purpose crossbred cows lactating from 2000 to 2005 at the Universidad Nacional de Agricultura de Honduras (UNA). The lactation curve and lactation parameters of interest were the scaling factor to represent yield at the beginning of lactation (a), the factor associated with the inclining (b) and declining (c) slopes of the lactation curves, and the milk yield at initial day of lactation (MY₂₀), peak milk yield (MY_max), day at peak milk yield (t_max), and the total milk yield (TM) per lactation, respectively. The incomplete gamma function (Wood function) was used to estimate lactation curve and lactation parameters from daily milk records of H × B, H × BS and BS × B crossbred cows. The environmental, additive and non-additive genetic effects on lactation curve and lactation parameters were estimated using Dickerson and Kinghorn models. The coefficients of determination of fitness of Wood's function (R²) ranged from 80% to 97% with an average of 93%. The lactation curve of the crossbred cows was similar to those reported for dairy cows grazing in the tropics. Lactation parameters such as MY_max, t_max and TM were significantly (P < 0.05) influenced by environmental sources of variation suggesting the necessity of differential management strategies. The moderate to large positive phenotypic correlation of MY_max and TM indicate that one of the milk yield parameters could be used as a selection criterion to improve either one or both traits. Despite the fact that both genetic models showed similar patterns, the absolute value of the parameters varied. For both models, individual additive genetic breed effect for H breed were significant (P < 0.05) and contributed more to TM than the BS breed. In the Dickerson model, highly positive significant (P < 0.01) effect on TM for H×BS and BS×B crosses was found. The Kinghorn model did not show significant effects of dominance on this parameter. The estimate of recombination effect for all crosses involving B breed were negative and significant (P < 0.05) for positive correlated lactation curve parameters. Although the inclusion of non-additive effects on crossbreeding genetic effects were not all significant for lactation curve and lactation parameters, non-additive effects should be taken into account to improve the Honduran dairy cattle production management.     

Comparison of carcass and meat characteristics of Brahman grade cattle (Bos indicus) and crossbred water buffalo (Bubalus bubalis)

This study was conducted to determine and compare the live traits, carcass yield and the physical, chemical, processing and sensory properties of meat from 20 Brahman grade cattle (crossbred cattle) and crossbred water buffalo (Philippine carabao × Murrah, Bulgarian or Indian) with an average age and weight of 29 months and 434 kg, respectively. The animals were fed a similar diet for 180 days before slaughter. A survey was performed to establish consumer meat preference between the two species. Live weights before slaughter of the two species were found to be different (P < 0.05) with the crossbred water buffalo showing higher bodyweight. However, the crossbred water buffalo had a lower (P < 0.05) dressing yield based on hot carcass weight and chilled carcass weight. The lower dressing yield of crossbred water buffalo can be attributed to its higher (P < 0.05) weights of edible and non‐edible slaughter by‐products. The chilled carcass yield of the forequarters and hindquarters from crossbred cattle and crossbred water buffalo were comparable when expressed as percent of live weight and chilled carcass weight. The estimated lean yield was higher in crossbred cattle than crossbred water buffalo. Crude protein, ash, fat, cholesterol, myofibrillar, sarcoplasmic and insoluble protein contents of the beef and carabao meat were all similar. Water holding capacity, pH, muscle fiber diameter, tenderness, firmness and marbling score in carabeef were all comparable to the beef. Redness was found to be higher (P < 0.05) in carabeef than the beef as measured with a color meter. The consumer meat preference survey showed that 55.9% selected the beef while 44.1% preferred carabeef. The color and amount of fat on the outside of the beef sample were primary in buyer selection.     

Blood biochemical profiles of thai indigenous and Simmental x Brahman crossbred cattle in the Central Thailand

Plasma biochemical profiles were studied in 112 mature (3 to 5-year-old) healthy cattle comprised of 61 Thai indigenous and 51 Simmental x Brahman crossbred male and cyclic female cattle at Nongkwang (Central Thailand) Livestock Research and Breeding Center, Thailand. Data were analysed for the effect of breed and sex. The results showed that the plasma glucose and gamma-glutamyl transferase (GGT) in the two breeds were significantly (P < 0.05) different. Furthermore, the urea, creatinine, albumin, total protein, aspartate amino transferase (AST), alanine amino transferase (ALT) and alkaline phosphatase (ALP) levels in Thai indigenous were significantly (P < 0.01) higher than in crossbred cattle. However, creatine kinase did not significantly differ in crossbred and indigenous animals. A sex difference was found in glucose level with male Thai indigenous having significantly higher levels (P < 0.05) than the other three groups. Plasma urea concentration in male crossbred cattle was lower than in the other groups (P < 0.05). Female crossbred cattle had significantly (P < 0.05) lower plasma creatinine levels than the other animals. Furthermore, levels of albumin in male and total protein in female crossbred were the lowest (P < 0.05) among the groups. The AST, ALT, ALP and GGT levels were significantly (P < 0.05) different between male and female. Female crossbred cattle had the lowest (P < 0.05) AST and GGT levels, whereas lowest (P < 0.05) ALT and ALP concentration was determined in male individuals of these breeds.