تاثیر پرورش گروهی و انفرادی بر عملکرد، فراسنجه‌های خونی، تخمیر شکمبه، رفتار و سلامت گوساله‌های شیری

هدف از این مطالعه، مقایسه نگهداری گوساله های شیرخوار در جایگاه انفرادی یا گروهی بر عملکرد، رشد اسکلتی، خون، رفتار، تخمیر شکمبه و سلامت بود. تیمارها شامل گوساله های پرورش یافته در 1) جایگاه های انفرادی (2 × 1/5 مترمربع) و یا 2) جایگاه های گروهی (4 × 3 مترمربع، 4 گوساله/جایگاه) بود. مصرف خوراک به‌طور روزانه، وزن کشی در زمان تولد، 28، 63، و 90 روزگی و رشد اسکلتی در ابتدا و انتهای دوره ثبت شدند. نمونه خون چهار روز قبل و بعد از شیرگیری و مایع شکمبه در روزهای 50 و 80 روزگی جمع آوری و رفتارها در دوره های 24 ساعت در روزهای 60 و 89 روزگی ثبت شد. مصرف خوراک، افزایش وزن روزانه، وزن بدن و رشد اسکلتی در دوره های مختلف تفاوت معنی داری نداشت. دفعات و طول مدت بیماری اسهال و پنومونی، کل درمان بیماری ها، تولید اسیدهای چرب فرار و ph شکمبه در بین تیمارها تفاوتی نداشت. سطح گلوکز و نیتروژن اوره خون نیز در بین تیمارها متفاوت نبود، ولی سطح کلسترول در گوساله های انفرادی در مقایسه با گوساله های گروهی در قبل و بعد از شیرگیری بیشتر بود. رفتارهای بازی، تیمار کردن، و مکیدن متقابل در گوساله های گروهی و سایر رفتارهای دهانی غیر تغذیه ای در گوساله های انفرادی در قبل از شیرگیری بیشتر بود. در پس از شیرگیری که تمام گوساله ها به‌صورت گروهی بودند، تفاوت معنی داری در رفتارها مشاهده نشد. به‌طور کلی، نتایج نشان داد که گروه‌بندی زودهنگام گوساله ها در مقایسه با پرورش در جایگاه های انفرادی اثری بر عملکرد، تخمیر شکمبه، و سلامت گوساله ها در قبل و بعد از شیرگیری نداشت، ولی منجر به بهبود رفاه (افزایش فعالیت های بازی و تیمار کردن و کاهش رفتارهای دهانی غیر تغذیه ای) گوساله ها در دوره قبل از شیرگیری شد.

effect of group and individual breeding on performance, blood parameters, ruminal fermentation, behavior and health of dairy calves

introduction: in most dairy farms, calves are housed individually during the milk-feeding period and will only introduce to social groups after weaning. individual housing can help keep calves healthy by reducing disease transmission and incidence behavioral problems such as cross-sucking as well as providing individual feeding and health-care of the calf. nevertheless, individual rearing systems through lack of social contact can compromise the welfare of the calf. calves are social animals, thus keeping calves in groups can promote more normal social behavior. also, social housing results in decreased labor costs associated with calf rearing, increased solid feed intake, weight gains, and less fear of novel social situations. despite all the performance and behavioral advantages in calves with social housing compared to individually housing, there are concerns about the close relationship between calves and the risk of disease transmission. it has been reported a higher frequency of diarrhea in socially housed calves compared with individually housed calves at week 3. thereby the risk of morbidity and mortality can be reduced if calves are grouped after 3 weeks of age onwards. also, no considerable differences were observed for social behaviors between calves housed together from birth compared with those housed together from 3 week of life. research is needed to establish best practices to rear the calves whilst improving the welfare, health, and growth of dairy calves. therefore the aim of this experiment was to investigate the effect of individual or group housing (from 4 weeks) on performance, blood parameters, ruminal fermentation, behavior, and health of dairy calves.materials and methods: a total of 32 holstein calves were separated from their dams immediately after birth, weighed, and placed in individual pens. then at 28 ± 2 d, calves were randomly assigned to either an individual pen (n = 16 calves, 1.5×2 m2) or group pen (4 calves/pen, n = 16 calves, 3×4 m2). all calves were offered a step-up/step-down method of milk feeding (4, 6, 8, 6, 4, and 2 l/d) and weaned at d 63. the study finished when calves reached 90 d of age. feed intake was determined daily. calves were weighed at birth, 28, 63, and 90 d of the age. body measurements including body length, body girth, withers height, heart girth, hip height, and hip width of the calves were measured at the start and end of the study. blood samples were collected at d 4 before and d 4 after weaning for measurement of glucose, cholesterol, and bun concentration. behavior parameters (playing, cross-sucking, grooming, and non-nutritive oral behavior) were monitored by visual observations of all calves at the 60 and 89 d of age for a period of 24 h. calf health was checked every day for fecal scoring, general appearance scoring, and respiratory scoring. also, diarrhea and pneumonia diagnoses and treatment of calves were recorded. on 50 and 80 d of age, ruminal fluid samples were collected from male calves for the measurement of ph and analysis of volatile fatty acids.results and discussion: there was no significant difference between housing for starter intake, total dry matter intake, and adg during pre-weaning, post-weaning, and the total period of the study. also, bw (birth, 28, 63, and 90 d) and skeletal growth (initial and final of the study) were not affected by housing. we observed no housing effect on glucose and bun plasma, however, cholesterol concentration was greater in individual calves than group calves at pre- and post-weaning, which is probably related to the greater stress of individual calves than group calves during weaning. ruminal ph, total vfa concentration, the concentration of acetate, propionate, butyrate, iso-butyrate, isovalerate, valerate, and acetate to propionate ratio in ruminal fluid were similar between treatments.